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Efficacy of combining varietal resistance with harvest time and planting date for the management of Sitophilus zeamais Motschulsky infestation in stored maize
Journal of Stored Products Research 60 (2015) 31e35
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Efficacy of combining varietal resistance with harvest time and planting date for the management of Sitophilus zeamais Motschulsky infestation in stored maize U. Zakka a, *, N.E.S. Lale a, O.C. Umeozor b a
University of Port Harcourt, Faculty of Agriculture, Department of Crop and Soil Science, Port Harcourt, Nigeria University of Port Harcourt, College of Natural and Applied Science, Faculty of Biological Sciences, Department of Animal and Environmental Biology, Port Harcourt, Nigeria b
a r t i c l e i n f o
a b s t r a c t
Article history: Accepted 25 October 2014 Available online 14 November 2014
The combination of varietal resistance with three harvest times and planting dates for efficient storage of maize against Sitophilus zeamais infestation was evaluated in the Niger Delta region of Nigeria for two seasons. Seven maize varieties made up of three susceptible local maize cultivars (Akparike, Bende and Ogbia muno) and four improved resistant varieties (ACR.97 TZL COMP.1-W, TZL COMP.4C2, ADV.NCRESTR and BG 97 TZE COMP.3XL) were used. There were significant differences in the number of teneral adults among harvest times in all the planting dates in both years. Maize harvested when the cobs were completely dry at the latest harvest time (HVT 3) suffered significantly higher weight losses. In 2009, the highest susceptibility was apparent in a local variety Akparike planted on 17 October (PD 1) and harvested at HVT 3 by which time the cobs had completely turned yellow. Combining early planting and early harvest with resistant varieties could be an appropriate tactic for resource-poor farmers to effectively manage maize weevils in the store in the Niger Delta agro-ecological zone. © 2014 Elsevier Ltd. All rights reserved.
Keywords: Maize weevil Sitophilus zeamais Infestation Planting date Harvest time
1. Introduction Maize is a major food crop and livestock feed in Africa, the Americas and Asia (Bergvinson, 2000). It is the third most important cereal after wheat and rice globally and the most widely distributed (Siwale et al., 2009). It is popular for being more resistant to pests and diseases and easier to store and process than traditional food cereals including sorghum and millet (Karaya et al., 2009). The major constraint to utilization of maize in the tropics and subtropics is the attack by maize weevil (Sitophilus zeamais Motschulsky) (Akob and Ewete, 2007). Semple et al. (1992) concluded that maize more than any other cereal, is prone to field infestation by field-to-store pests; they further reiterated that maize is heavily attacked when standing in the field at the early stage of ripening by S. zeamais which may complete one or even two life cycles before harvest. Adult weevils and larvae feed on undamaged grains and frequently cause severe
* Corresponding author. Tel.: þ234 (0)8065703350. E-mail address: [email protected] (U. Zakka). http://dx.doi.org/10.1016/j.jspr.2014.10.005 0022-474X/© 2014 Elsevier Ltd. All rights reserved.
powdering, rendering the product unfit for human consumption (Ofuya et al., 2008). However, according to Trematerra et al. (2007), S. zeamais adults are more attracted to insect-damaged maize kernels than intact or mechanically damaged kernels. Partially damaged maize grains manifest loss in weight, poor marketability, quality deterioration and low viability (Enobakhare and Law-Ogbomo, 2002). Harvesting maize is not so closely tied to a particular time as with other cereals; however, harvested maize is usually left out for further drying and this, coupled with undue delay in harvesting increases infestation by pests (Katinila et al., 1998). Harvest time modification has been shown to be an effective strategy for reducing field-infestation of cowpea by Callosobruchus maculatus (Fab.), another field-to-store insect pest (Olubayo and Port, 1997). Obeng-Ofori (2008) advocated harvesting at optimal time to minimize field infestation prior to harvest as a good IPM strategy for the control of stored pests. Reports of similar studies on S. zeamais are very scarce in the literature; in this study, the combination of varietal resistance, time of harvest and planting date was assessed as a possible strategy for the management of S. zeamais in stored maize. It was hoped that the study would provide an appropriate technology for storage of maize in the Niger
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U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35
Delta region and other parts of the country with similar agroecological characteristics.
2.3. Grain weight loss Grain weight loss was determined as described by Lale (2002):
2. Materials and methods The experiment was conducted at the Teaching and Research Farm of the Faculty of Agriculture, University of Port Harcourt located at latitude 4.54oN and longitude 6.55oE with an elevation of approximately 20 m above sea level. Mean annual rainfall is variable and ranges from 2000 mm to 2680 mm. Annually, the mean monthly maximum temperature ranges from 28 C to 33 C while the mean monthly minimum temperature ranges from 20 C to 23 C. 2.1. Experimental procedures Seven maize cultivars comprising five hybrids (ACR.97 TZL COMP.1-W, TZL COMP.4C2, ADV.NCRE-STR and BG 97 TZE COMP.3XL) developed by the International Institute of Tropical Agriculture, Ibadan, Nigeria and obtained from their germplasm and three local cultivars (Akparike, Bende and Ogbia muno) obtained from the open market in Elibrada Emuoha, Rivers State, Nigeria were sown on 17 October (Planting Date 1; PD 1), 1 November (Planting date 2; PD 2) and 15 November (Planting Date 3; PD 3) in 2008 and 2009 cropping seasons in a complete randomized block experiment (Sastawa et al., 2002). Each plot measured 3 m by 6.6 m. In the block design the treatments were replicated three times. Seeds were sown on each plot manually with double rows containing 10 stands of each maize variety at a depth of 2e3 cm by placing 3e4 seeds/hole. The plants were thinned after 2 weeks to two plants per stand. Spacing between rows and plants were 0.75 and 0.3 m, respectively, and distance between treatments and replicates was 1.5 m. Fertilizer was applied 3weeks after planting (WAP) and 6 WAP to give 60 kg N (119 g N/ plot) and 60 kg P2O5 ha1 (119 g P2O5/plot) as recommended for the area in two splits (ICAR, 2006). The fields were kept weed-free by hand weeding. 2.2. Harvest time All mature cobs from each treatment combination were harvested separately at three different stages (at the commencement of yellowing (Harvest 1; HVT1), at advanced yellowing (Harvest 2; HVT2) and at complete drying (Harvest 3, HVT3)) to evaluate the effectiveness of the combination of the various techniques in mitigating the introduction of S. zeamais into the store. The cobs were left to dry for 35 days under shade with each harvest time kept in a cluster and kept 1 m apart. The distance of 1 m allowed between treatments was to ensure that cobs from different treatments were not mixed rather than for preventing dispersal of insects, which at this stage were still confined to developing within the grains. After drying, cobs from each treatment combination were shelled by hand and the grains collected on a piece of white cloth. Twenty g from each treatment lot were weighed using a sensitive Mettler balance (Model A & D FX-6000), placed in 1-L Kilner jars and left undisturbed under laboratory conditions (25e30 C and 70e90 % r.h.) until teneral adults started emerging (Zakka, 2005). Records of the number of F1 adults that emerged was taken daily for up to three weeks by emptying the content of each jar carefully onto white paper and counting and removing adult insects to determine the daily emergence pattern. At the end of the 21 days when no adults were recorded consistently for up to 4 days, the content of each jar was carefully placed back into the jar and the jar kept in its original position.
%weight loss ¼
½UaN ðU þ DÞ 100 UaN
where U ¼ weight of undamaged fraction (the seeds in the sample that were not damaged) in a sample N ¼ total number of grains in a sample Ua ¼ average weight of one undamaged kernel (kernels without weevil emergence hole) D ¼ weight of damaged fraction in a sample. This was confirmed by the modified gravimetric method of Compton et al. (1998) by counting damaged grains and weighing the final samples using the formula:
%weight loss ¼
Pnd Pfa Pnd
where Pnd ¼ weight of non damaged kernels Pfa ¼ final weight of sample. 2.4. Statistical analysis Data collected were subjected to analysis of variance (ANOVA) using the statistical software package SAS 2000 version and according to the procedures reported by Gomez and Gomez (1983). 3. Results Table 1 shows the F1 adult progeny of maize weevil that emerged from maize seeds planted on different dates and harvested at different times. There were significant differences (P 0.05) in the mean numbers of teneral adults that emerged in both years among harvest times for all the planting dates with more weevils emerging in maize cultivars harvested latest (HVT 3- where the cobs were allowed to dry completely in the field). Similarly, in both years significantly more teneral F1 weevils emerged from maize planted early (PD1) than from maize planted later; progeny number with respect to planting date was in the following order: PD1 (17 October) > PD2 (1 November) > PD3 (15 November). Significantly more F1 S. zeamais adults emerged from maize planted on 17 October (PD 1) in both 2008 and 2009. In 2009, grain weight loss in maize harvested just at the time of yellowing (HVT 1) and in that harvested when they were allowed to Table 1 Mean numbers of adult S. zeamais emerged at different harvest times under different planting dates as a management technique against S. zeamais infestation. Planting date HVT
HVT1 HVT2 HVT3 HVT1 HVT2 HVT3
17 Oct. (PD1) 2008 15.14c 17.10b 21.71a 2009 22.38c 24.57b 29.24a
1 Nov. (PD2)
15 Nov.(PD3)
10.10c 12.05b 15.90a
8.38c 9.95b 12.24a
17.00c 17.62b 22.38a
12.33c 19.43a 15.52b
SED: 1.35 (2008) 3.50 (2009). Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35 Table 2 Mean weight loss (g) in maize grains infested by S. zeamais at different harvest times under different planting dates as a management technique against S. zeamais. Harvest time/planting date
Planting date 17 Oct. (PD1)
HVT1 HVT2 HVT3 HVT1 HVT2 HVT3
2008 1.92a 1.81a 1.51a 2009 2.65a 1.41b 2.47a
1 Nov. (PD2)
15 Nov. (PD3)
1.49b 1.92a 1.76ab
1.64a 1.61a 1.48a
2.21a 1.50b 2.17a
2.48a 1.39c 2.15b
SED: 0.79 (2008) 0.48 (2009). Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
dry completely in the field (HVT 3) had significantly higher weight losses (Table 2). The least numbers of weevil progeny were recorded in varieties TZL COMP.4C2 and ACR.97 TZL COMP.1-W in 2008 and in BG 97 TZE COMP.3XL and ADV.NCRE-STR in 2009. In maize harvested latest (HVT 3) in both years a similar trend was exhibited with Akparike and Ogbia muno varieties as they supported a significantly higher (P 0.05) number of weevil progeny than cultivar TZL COMP.4C2 which supported the least number (Table 3). In 2008, maize planted on 17 October and harvested when the cobs just turned yellow (HVT 1) suffered a significantly higher weight loss in Ogbia muno variety, followed by BG 97 TZE COMP.3XL and ACR.97 TZL COMP.1-W. In 2009, however, Ogbia muno, Bende, Akparike and ACR.97 TZL COMP.1-W suffered significantly higher (P 0.05) grain weight losses (Table 4). 4. Discussion 4.1. Harvest time as a suitable tool in curbing the introduction of S. zeamais to store and a practical management technique in maize production The length of time that maize and other cereals are left in the field before harvest plays a great role in determining the insect
33
pest load especially in the case of field-to-store pests. The result that late harvest of maize, where the cobs were allowed to dry completely in the field (HVT 3), supported a higher number of adult weevils confirms the work of Olubayo and Port (1997) on C. maculatus in cowpea where it was reported that cowpea seeds harvested very late supported more storage bruchids than those harvested early or at the recommended harvest time. Early harvest of maize just at the point when the cobs begin to show signs of yellowing coincides with the point of physiological maturity and suggests it to be the best time for harvesting maize in the study area. It is evident from the present results that late harvesting of maize tends to increase the number of both teneral adults and/or immature stages that will further develop and reproduce in store. Early harvest might, therefore, offer the maize an opportunity to escape significant field invasion and colonization by the weevils in the field (Mejia, 2003). However, harvesting as soon as the maize attains physiological maturity would mean repeated harvests and increased labor costs, though these would most probably be offset by the increased value of sound maize saved from infestation by weevils. Caneppele et al. (2003) quoting from a CONAB-Companhia National de Abastecimento report, refer to an increase of 33% in maize production over a period of about 5 years in Brazil due to adoption of good harvest practices. It is, however, not uncommon for either farmers or seed merchants to leave their crops in the field for unreasonably long periods of time thereby exposing the crops to greater infestation. Staggered harvesting of maize as advocated by this finding should reduce weevil infestation. This practice was suggested by Caswell (1970) for cowpea harvest as a mitigating measure against bruchids in Nigeria where regular weekly harvesting of cowpea reduces cowpea bruchid infestation by two-thirds. Olubayo and Port (1997) reiterated that it is evident that a crop harvested either early or on time during the harvest season would minimize bruchid damage in the field and, subsequently in the store. Timely and well staggered harvest will reduce the pressure on labor to harvest maize in a single lot as reported by Kabeh and Lale (2004), who stated that inadequate labor had a direct effect on post-harvest loss, especially in large scale farming. It is therefore, wise to harvest maize early and periodically as predicted by this study instead of waiting for a
Table 3 Teneral adult S. zeamais emerged in different maize varieties under different harvest times and planting dates as a management technique against S. zeamais infestation. Treatment (planting date and harvest time) Variety 2008 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 2009 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 LSD (P 0.05) PD Variety PD Variety
PD1HVT1
PD1HVT2
PD1HVT3
PD2HVT1
PD2HVT2
PD2HVT3
PD3HVT1
PD3HVT2
PD3HVT3
12.00c 11.00c 21.00a 19.00a 18.00a 16.33b 8.67d
11.67e 12.67e 23.67b 26.33a 16.00d 21.00c 8.33f
15.67e 21.67c 28.00a 29.67a 19.33d 25.33b 12.33f
7.67b 7.00b 12.00a 13.33a 12.00a 12.33a 6.33b
7.00c 13.00b 17.33a 13.67b 11.00b 16.00a 6.33c
11.33c 18.00b 21.33a 19.33ab 15.67 19.00ab 6.67d
7.00b 6.33bc 11.67a 9.67b 8.33b 9.67b 6.00c
7.00d 10.00c 15.67a 10.67c 8.00dc 13.00b 5.33e
10.00c 11.67c 16.33a 14.67b 13.67bc 13.67bc 5.67d
22.33b 15.33cd 29.67a 29.33a 18.00bc 30.67a 11.33d
24.33b 19.67b 31.67a 32.00a 22.00b 32.33a 10.00c
24.67bc 26.33b 38.33a 34.67a 28.67b 34.00a 18.00c
13.67b 13.33b 27.00a 17.33b 13.67b 23.33a 10.67b
20.33a 13.67b 25.33a 23.00 10.00b 23.33a 7.67c
20.00b 19.00b 33.33a 30.00a 16.33b 29.00a 9.00c
14.33a 8.33b 17.33a 13.00ab 11.00ab 13.67ab 8.67b
17.67ab 12.00bc 19.67a 20.67a 12.33b 20.00a 6.33c
18.67bc 17.67c 27.00a 24.33ab 18.33bc 19.67bc 10.33d
df 8 6 48
FPr (2008) <0.001 <0.001 <0.001
PD Variety PD Variety
Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
df 8 6 48
FPr (2009) <0.001 <0.001 0.200
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U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35
Table 4 Mean weight loss (g) in maize grains infested by S. zeamais in different varieties under different harvest times and different planting dates as a management technique against S. zeamais infestation. Treatment (planting date and harvest time) Variety 2008 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 2009 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 LSD (P 0.05) PD Variety PD Variety
PD1HVT1
PD1HVT2
PD1HVT3
PD2HVT1
PD2HVT2
PD2HVT3
PD3HVT1
PD3HVT2
PD3HVT3
2.16ab 1.89b 1.10b 1.03b 2.29ab 3.99a 1.02b
2.38a 2.27a 1.08a 1.42a 1.44a 1.95a 2.16a
1.63ab 1.25ab 2.20a 1.59ab 1.52ab 1.46ab 0.90b
1.25ab 1.77ab 0.95b 1.32ab 1.92ab 2.18a 1.04ab
1.39bc 2.20a-c 1.49bc 1.29bc 2.81ab 0.99c 3.24a
3.54a 2.04a 2.05a 1.62b 1.23b 0.95b 0.85b
1.36b 2.19b 1.28b 0.75 1.81b 3.17a 0.91b
2.06a 1.90a 1.31a 1.41a 2.23a 1.59a 0.79a
0.80b 2.47a 1.25ab 1.20ab 1.90ab 1.76ab 0.99ab
3.24a 1.89b 3.07a 3.18a 2.96a 3.54a 0.66c
1.17b 1.21b 1.48a 1.79a 1.11b 2.16a 0.92b
3.03a 2.25a 2.71a 3.02a 2.44a 3.07a 0.77b
2.09bc 1.73cd 2.89ab 2.66ab 1.70cd 3.36a 1.04d
1.46a-c 1.25b 2.02ab 2.15a 1.35bc 1.43bc 0.84c
1.89ab 2.01a 2.70a 2.71a 2.32a 2.61a 0.98b
2.17b 1.20c 3.54a 3.16a 2.07b 3.48a 0.94c
1.60a 1.18ab 1.98a 1.77a 1.17ab 1.63a 0.37b
3.04a 1.69b 2.05b 2.71ab 2.58ab 2.49ab 0.53c
df 8 6 48
FPr (2008) 0.687 0.008 0.045
PD Variety PD Variety
df 8 6 48
FPr (2009) <0.001 <0.001 0.14
Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
single harvest when all the cobs are completely dry and when there is greater pressure on labor. 4.2. Effective planting time as a tool in mitigating maize weevil attack in stored maize The results suggest that planting maize early (17 October) may predispose the crops to the peak of insect abundance and planting maize around 1 November could be an appropriate planting date of maize to significantly reduce weevil infestation in the study area. Tolerance and resistance also include the ability of the crop to escape invasion or the peak period of damage. If this strategy is adopted it would ensure a relatively pest-free maize in store. This finding concurs with that of Sastawa et al. (2002) who recorded a significantly higher percentage of stem borers in millets sown in the Sudan savanna on 5 August than those sown earlier on 14 July, 21 July and 28 July. Lale and Sastawa (2000) reported a decrease in infestation and damage with delayed sowing and confirmed that head miners became less important as the season advanced and concluded that early sowing of millet causes the coincidence of the heading of these millets with the period of peak activity of the beetles. Ajayi (1990) however, found that early sown millet suffered less stem borer damage than late-sown millet in the Nigerian Guinea savanna. The success of phenological asynchrony as a method of pest management is however dependent, to a large extent, on the nature of the agroecology in which the crop is cultivated; maize is cultivated entirely under rain-fed conditions and the availability of rain determines when cultivation can commence and consequently when harvesting could be done. The integration of planting date with other cultural methods and varietal resistance as a means of controlling S. zeamais infestation is a follow-up on similar work by Lale and Sastawa who reported that by adjusting the planting date of cereal crops damage by meloid beetles was greatly reduced. Other studies on the technique of modifying planting date include those of Nwanze (1997) and Sastawa et al. (2002); in each of these studies, the use of resistant cultivars and manipulation of planting date were reported to be effective methods for the management of stem borers and
head miners in cereal crops. Sastawa et al. (2002) concluded that the method is cost effective from the farmers' point of view and is likely to be adopted easily by subsistence farmers. Acknowledgment The authors would like to thank AAU (pc/6) for funding the work and IITA Ibadan Nigeria for providing the improved varieties used in the studies. The comments by two anonymous reviewers towards improving the quality of this paper are acknowledged. References Ajayi, O., 1990. Possibilities of integrated control of millet stem borer, Acigona ignefusalis Hampson (Lepidoptera: Pyralidae) in Nigeria. Insect Sci. Appl. 2, 109e117. Akob, C.A., Ewete, F.K., 2007. The efficacy of ashes of four locally used plant materials against Sitophilus zeamais (Coleoptera: Curculionidae) in Cameroon. Int. J. Trop. Insect Sci. 27, 21e26. Bergvinson, D.J., 2000. Storage pest resistance in Maize. Maize Res. Highlights 1999e2000. Caneppele, M.A.B., Caneppele, C., Lazzari, F.A., Lazzari, S.M.N., 2003. Correlation between the infestation level of Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae) and the quality factors of stored corn, Zea mays L. (Poaceae). Rev. Bras. Entomol. 17, 625e630. Caswell, G.H., 1970. The storage of cowpea in the northern states of Nigeria. Proc. Agric. Soc. Niger. 5, 4e6. Compton, J.A.F., Flovo, A., Ofosu, A., Agbo, B., 1998. The modified count and weight method and improved procedure for assessing weight loss in stored maize cobs. J. Stored Prod. Res. 34, 277e285. Enobakhare, D.A., Law-Ogbomo, K.E., 2002. Reduction of post harvest loss caused by Sitophilus zeamais (Motsch) in three varieties of maize treated with plant products. Post Harvest Sci. 1, 1e6. Gomez, K.A., Gomez, A.A., 1983. Statistical Procedures for Agricultural Research, second ed. In: An International Rice Research Institute Book Wiley-Interscience Publications, New York. ICAR, 2006. Handbook of Agriculture, fifth ed. Indian Council of Agricultural Research, Krishi Anusandhan Bhavan, New Delhi. Kabeh, J.D., Lale, N.E.S., 2004. Effect of Pre-harvest sprays of neem (Azadirachta indica A. Juss) seed products and pirimiphos-methyl and harvest time modification on infestation of cowpeas by storage bruchids in the field and store in Maiduguri, Nigeria. Niger. J. Entomol. 21, 104e116. Karaya, H., Njoroge, K., Mugo, S., Nderitu, H., 2009. Combining ability among twenty insect resistant maize inbred lines resistant to Chilo partellus and Buseola fusca stem borers. Int. J. Plant Prod. 3, 115e126. Katinila, N., Verkuijl, H., Mwangi, W., Anandajayasekeram, P., Moshi, A.J., 1998. Adoption of Maize Production Technologies in Southern Tanzania. Mexico, D.F.:
U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35 International Maize and Wheat Improvement Center (CIMMYT), the United Republic of Tanzania, and the Southern Africa Centre for Cooperation in Agricultural Research (SACCAR). Lale, N.E.S., Sastawa, B.M., 2000. Evaluation of host plant resistance, sowing date modification and intercropping as methods for the control of Mylabris and Coryna species (Coleoptera: Meloidae) infesting pearl millet in the Nigerian Sudan savanna. J. Arid Environ. 46, 263e280. Lale, N.E.S., 2002. Stored Product Entomology and Acarology in Tropical Africa, first ed. Mole Publications (Nigeria) Ltd, Maiduguri. Mejia, D., 2003. Maize overall Losses. Post-harvest operation, Agro-industry and Infrastructure, Food and Agricultural Organization of the United Nations Regional Office for the Near East, Cairo, Egypt. Nwanze, K.F., 1997. Integrated management of stem borers of sorghum and pearl millet. Insect Sci. Appl. 17, 1e8. Obeng-Ofori, D., 2008. Major stored product arthropod pests. In: Cornelius, E.W., Obeng-Ofori, D. (Eds.), Post-harvest Science and Technology. Teaching and Learning Innovation Fund (TALIF). Smartline Publishers, Accra, Ghana. Ofuya, T.I., Idoko, J.E., Akintewe, L.A., 2008. Ability of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) from four locations in Nigeria to infest and damage three varieties of maize, Zea mays L. Niger. J. Entomol. 25, 34e39. Olubayo, F.M., Port, G.R., 1997. The efficacy of harvest time modification and intercropping as methods of reducing the field infestation of cowpea by storage bruchids in Kenya. J. Stored Prod. Res. 33, 271e276.
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Sastawa, B.M., Lale, N.E.S., Ajayi, O., 2002. Evaluating host plant resistance and sowing date modification for the management of the stem borer, Coniesta ignefusalis Hampson and the head miner Heliocheilus albipunctella de Joannis infesting pearl millet in the Nigerian Sudan savanna. J. Plant Dis. Prot. 109, 530e542. Semple, R.L., Hicks, P.A., Lozare, J.V., Castermans, A., 1992. In: Proceedings and Selected Papers from the Regional Training Course on Integrated Pest Management Strategies in Grain Storage Systems, Conducted by the National Postharvest Institute for Research and Extension (NAPHIRE). Department of Agriculture, June 6-18 1991. A REGNET (RAS/86/189) Publication in Collaboration with NAPHIRE, Philippines. Siwale, J., Mbata, K., Microbert, J., Lungu, D., 2009. Comparative resistance of improved maize genotypes and landraces to maize weevil. Afr. Crop Sci. J. 17, 1e16. Trematerra, P., Valente, A., Athannassiou, C.G., Kavallieratos, N.G., 2007. Kernelkernel interactions and behavioural response of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). Appl. Entomol. Zool. 42, 129e135. Zakka, U., 2005. Development of Dermestes maculatus (De Geer, 1776) (Coleoptera: Dermestidae) on Different Fish Substrates. M Phil. thesis in Entomology. University of Ghana.
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Journal of Stored Products Research journal homepage: www.elsevier.com/locate/jspr
Efficacy of combining varietal resistance with harvest time and planting date for the management of Sitophilus zeamais Motschulsky infestation in stored maize U. Zakka a, *, N.E.S. Lale a, O.C. Umeozor b a
University of Port Harcourt, Faculty of Agriculture, Department of Crop and Soil Science, Port Harcourt, Nigeria University of Port Harcourt, College of Natural and Applied Science, Faculty of Biological Sciences, Department of Animal and Environmental Biology, Port Harcourt, Nigeria b
a r t i c l e i n f o
a b s t r a c t
Article history: Accepted 25 October 2014 Available online 14 November 2014
The combination of varietal resistance with three harvest times and planting dates for efficient storage of maize against Sitophilus zeamais infestation was evaluated in the Niger Delta region of Nigeria for two seasons. Seven maize varieties made up of three susceptible local maize cultivars (Akparike, Bende and Ogbia muno) and four improved resistant varieties (ACR.97 TZL COMP.1-W, TZL COMP.4C2, ADV.NCRESTR and BG 97 TZE COMP.3XL) were used. There were significant differences in the number of teneral adults among harvest times in all the planting dates in both years. Maize harvested when the cobs were completely dry at the latest harvest time (HVT 3) suffered significantly higher weight losses. In 2009, the highest susceptibility was apparent in a local variety Akparike planted on 17 October (PD 1) and harvested at HVT 3 by which time the cobs had completely turned yellow. Combining early planting and early harvest with resistant varieties could be an appropriate tactic for resource-poor farmers to effectively manage maize weevils in the store in the Niger Delta agro-ecological zone. © 2014 Elsevier Ltd. All rights reserved.
Keywords: Maize weevil Sitophilus zeamais Infestation Planting date Harvest time
1. Introduction Maize is a major food crop and livestock feed in Africa, the Americas and Asia (Bergvinson, 2000). It is the third most important cereal after wheat and rice globally and the most widely distributed (Siwale et al., 2009). It is popular for being more resistant to pests and diseases and easier to store and process than traditional food cereals including sorghum and millet (Karaya et al., 2009). The major constraint to utilization of maize in the tropics and subtropics is the attack by maize weevil (Sitophilus zeamais Motschulsky) (Akob and Ewete, 2007). Semple et al. (1992) concluded that maize more than any other cereal, is prone to field infestation by field-to-store pests; they further reiterated that maize is heavily attacked when standing in the field at the early stage of ripening by S. zeamais which may complete one or even two life cycles before harvest. Adult weevils and larvae feed on undamaged grains and frequently cause severe
* Corresponding author. Tel.: þ234 (0)8065703350. E-mail address: [email protected] (U. Zakka). http://dx.doi.org/10.1016/j.jspr.2014.10.005 0022-474X/© 2014 Elsevier Ltd. All rights reserved.
powdering, rendering the product unfit for human consumption (Ofuya et al., 2008). However, according to Trematerra et al. (2007), S. zeamais adults are more attracted to insect-damaged maize kernels than intact or mechanically damaged kernels. Partially damaged maize grains manifest loss in weight, poor marketability, quality deterioration and low viability (Enobakhare and Law-Ogbomo, 2002). Harvesting maize is not so closely tied to a particular time as with other cereals; however, harvested maize is usually left out for further drying and this, coupled with undue delay in harvesting increases infestation by pests (Katinila et al., 1998). Harvest time modification has been shown to be an effective strategy for reducing field-infestation of cowpea by Callosobruchus maculatus (Fab.), another field-to-store insect pest (Olubayo and Port, 1997). Obeng-Ofori (2008) advocated harvesting at optimal time to minimize field infestation prior to harvest as a good IPM strategy for the control of stored pests. Reports of similar studies on S. zeamais are very scarce in the literature; in this study, the combination of varietal resistance, time of harvest and planting date was assessed as a possible strategy for the management of S. zeamais in stored maize. It was hoped that the study would provide an appropriate technology for storage of maize in the Niger
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U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35
Delta region and other parts of the country with similar agroecological characteristics.
2.3. Grain weight loss Grain weight loss was determined as described by Lale (2002):
2. Materials and methods The experiment was conducted at the Teaching and Research Farm of the Faculty of Agriculture, University of Port Harcourt located at latitude 4.54oN and longitude 6.55oE with an elevation of approximately 20 m above sea level. Mean annual rainfall is variable and ranges from 2000 mm to 2680 mm. Annually, the mean monthly maximum temperature ranges from 28 C to 33 C while the mean monthly minimum temperature ranges from 20 C to 23 C. 2.1. Experimental procedures Seven maize cultivars comprising five hybrids (ACR.97 TZL COMP.1-W, TZL COMP.4C2, ADV.NCRE-STR and BG 97 TZE COMP.3XL) developed by the International Institute of Tropical Agriculture, Ibadan, Nigeria and obtained from their germplasm and three local cultivars (Akparike, Bende and Ogbia muno) obtained from the open market in Elibrada Emuoha, Rivers State, Nigeria were sown on 17 October (Planting Date 1; PD 1), 1 November (Planting date 2; PD 2) and 15 November (Planting Date 3; PD 3) in 2008 and 2009 cropping seasons in a complete randomized block experiment (Sastawa et al., 2002). Each plot measured 3 m by 6.6 m. In the block design the treatments were replicated three times. Seeds were sown on each plot manually with double rows containing 10 stands of each maize variety at a depth of 2e3 cm by placing 3e4 seeds/hole. The plants were thinned after 2 weeks to two plants per stand. Spacing between rows and plants were 0.75 and 0.3 m, respectively, and distance between treatments and replicates was 1.5 m. Fertilizer was applied 3weeks after planting (WAP) and 6 WAP to give 60 kg N (119 g N/ plot) and 60 kg P2O5 ha1 (119 g P2O5/plot) as recommended for the area in two splits (ICAR, 2006). The fields were kept weed-free by hand weeding. 2.2. Harvest time All mature cobs from each treatment combination were harvested separately at three different stages (at the commencement of yellowing (Harvest 1; HVT1), at advanced yellowing (Harvest 2; HVT2) and at complete drying (Harvest 3, HVT3)) to evaluate the effectiveness of the combination of the various techniques in mitigating the introduction of S. zeamais into the store. The cobs were left to dry for 35 days under shade with each harvest time kept in a cluster and kept 1 m apart. The distance of 1 m allowed between treatments was to ensure that cobs from different treatments were not mixed rather than for preventing dispersal of insects, which at this stage were still confined to developing within the grains. After drying, cobs from each treatment combination were shelled by hand and the grains collected on a piece of white cloth. Twenty g from each treatment lot were weighed using a sensitive Mettler balance (Model A & D FX-6000), placed in 1-L Kilner jars and left undisturbed under laboratory conditions (25e30 C and 70e90 % r.h.) until teneral adults started emerging (Zakka, 2005). Records of the number of F1 adults that emerged was taken daily for up to three weeks by emptying the content of each jar carefully onto white paper and counting and removing adult insects to determine the daily emergence pattern. At the end of the 21 days when no adults were recorded consistently for up to 4 days, the content of each jar was carefully placed back into the jar and the jar kept in its original position.
%weight loss ¼
½UaN ðU þ DÞ 100 UaN
where U ¼ weight of undamaged fraction (the seeds in the sample that were not damaged) in a sample N ¼ total number of grains in a sample Ua ¼ average weight of one undamaged kernel (kernels without weevil emergence hole) D ¼ weight of damaged fraction in a sample. This was confirmed by the modified gravimetric method of Compton et al. (1998) by counting damaged grains and weighing the final samples using the formula:
%weight loss ¼
Pnd Pfa Pnd
where Pnd ¼ weight of non damaged kernels Pfa ¼ final weight of sample. 2.4. Statistical analysis Data collected were subjected to analysis of variance (ANOVA) using the statistical software package SAS 2000 version and according to the procedures reported by Gomez and Gomez (1983). 3. Results Table 1 shows the F1 adult progeny of maize weevil that emerged from maize seeds planted on different dates and harvested at different times. There were significant differences (P 0.05) in the mean numbers of teneral adults that emerged in both years among harvest times for all the planting dates with more weevils emerging in maize cultivars harvested latest (HVT 3- where the cobs were allowed to dry completely in the field). Similarly, in both years significantly more teneral F1 weevils emerged from maize planted early (PD1) than from maize planted later; progeny number with respect to planting date was in the following order: PD1 (17 October) > PD2 (1 November) > PD3 (15 November). Significantly more F1 S. zeamais adults emerged from maize planted on 17 October (PD 1) in both 2008 and 2009. In 2009, grain weight loss in maize harvested just at the time of yellowing (HVT 1) and in that harvested when they were allowed to Table 1 Mean numbers of adult S. zeamais emerged at different harvest times under different planting dates as a management technique against S. zeamais infestation. Planting date HVT
HVT1 HVT2 HVT3 HVT1 HVT2 HVT3
17 Oct. (PD1) 2008 15.14c 17.10b 21.71a 2009 22.38c 24.57b 29.24a
1 Nov. (PD2)
15 Nov.(PD3)
10.10c 12.05b 15.90a
8.38c 9.95b 12.24a
17.00c 17.62b 22.38a
12.33c 19.43a 15.52b
SED: 1.35 (2008) 3.50 (2009). Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35 Table 2 Mean weight loss (g) in maize grains infested by S. zeamais at different harvest times under different planting dates as a management technique against S. zeamais. Harvest time/planting date
Planting date 17 Oct. (PD1)
HVT1 HVT2 HVT3 HVT1 HVT2 HVT3
2008 1.92a 1.81a 1.51a 2009 2.65a 1.41b 2.47a
1 Nov. (PD2)
15 Nov. (PD3)
1.49b 1.92a 1.76ab
1.64a 1.61a 1.48a
2.21a 1.50b 2.17a
2.48a 1.39c 2.15b
SED: 0.79 (2008) 0.48 (2009). Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
dry completely in the field (HVT 3) had significantly higher weight losses (Table 2). The least numbers of weevil progeny were recorded in varieties TZL COMP.4C2 and ACR.97 TZL COMP.1-W in 2008 and in BG 97 TZE COMP.3XL and ADV.NCRE-STR in 2009. In maize harvested latest (HVT 3) in both years a similar trend was exhibited with Akparike and Ogbia muno varieties as they supported a significantly higher (P 0.05) number of weevil progeny than cultivar TZL COMP.4C2 which supported the least number (Table 3). In 2008, maize planted on 17 October and harvested when the cobs just turned yellow (HVT 1) suffered a significantly higher weight loss in Ogbia muno variety, followed by BG 97 TZE COMP.3XL and ACR.97 TZL COMP.1-W. In 2009, however, Ogbia muno, Bende, Akparike and ACR.97 TZL COMP.1-W suffered significantly higher (P 0.05) grain weight losses (Table 4). 4. Discussion 4.1. Harvest time as a suitable tool in curbing the introduction of S. zeamais to store and a practical management technique in maize production The length of time that maize and other cereals are left in the field before harvest plays a great role in determining the insect
33
pest load especially in the case of field-to-store pests. The result that late harvest of maize, where the cobs were allowed to dry completely in the field (HVT 3), supported a higher number of adult weevils confirms the work of Olubayo and Port (1997) on C. maculatus in cowpea where it was reported that cowpea seeds harvested very late supported more storage bruchids than those harvested early or at the recommended harvest time. Early harvest of maize just at the point when the cobs begin to show signs of yellowing coincides with the point of physiological maturity and suggests it to be the best time for harvesting maize in the study area. It is evident from the present results that late harvesting of maize tends to increase the number of both teneral adults and/or immature stages that will further develop and reproduce in store. Early harvest might, therefore, offer the maize an opportunity to escape significant field invasion and colonization by the weevils in the field (Mejia, 2003). However, harvesting as soon as the maize attains physiological maturity would mean repeated harvests and increased labor costs, though these would most probably be offset by the increased value of sound maize saved from infestation by weevils. Caneppele et al. (2003) quoting from a CONAB-Companhia National de Abastecimento report, refer to an increase of 33% in maize production over a period of about 5 years in Brazil due to adoption of good harvest practices. It is, however, not uncommon for either farmers or seed merchants to leave their crops in the field for unreasonably long periods of time thereby exposing the crops to greater infestation. Staggered harvesting of maize as advocated by this finding should reduce weevil infestation. This practice was suggested by Caswell (1970) for cowpea harvest as a mitigating measure against bruchids in Nigeria where regular weekly harvesting of cowpea reduces cowpea bruchid infestation by two-thirds. Olubayo and Port (1997) reiterated that it is evident that a crop harvested either early or on time during the harvest season would minimize bruchid damage in the field and, subsequently in the store. Timely and well staggered harvest will reduce the pressure on labor to harvest maize in a single lot as reported by Kabeh and Lale (2004), who stated that inadequate labor had a direct effect on post-harvest loss, especially in large scale farming. It is therefore, wise to harvest maize early and periodically as predicted by this study instead of waiting for a
Table 3 Teneral adult S. zeamais emerged in different maize varieties under different harvest times and planting dates as a management technique against S. zeamais infestation. Treatment (planting date and harvest time) Variety 2008 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 2009 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 LSD (P 0.05) PD Variety PD Variety
PD1HVT1
PD1HVT2
PD1HVT3
PD2HVT1
PD2HVT2
PD2HVT3
PD3HVT1
PD3HVT2
PD3HVT3
12.00c 11.00c 21.00a 19.00a 18.00a 16.33b 8.67d
11.67e 12.67e 23.67b 26.33a 16.00d 21.00c 8.33f
15.67e 21.67c 28.00a 29.67a 19.33d 25.33b 12.33f
7.67b 7.00b 12.00a 13.33a 12.00a 12.33a 6.33b
7.00c 13.00b 17.33a 13.67b 11.00b 16.00a 6.33c
11.33c 18.00b 21.33a 19.33ab 15.67 19.00ab 6.67d
7.00b 6.33bc 11.67a 9.67b 8.33b 9.67b 6.00c
7.00d 10.00c 15.67a 10.67c 8.00dc 13.00b 5.33e
10.00c 11.67c 16.33a 14.67b 13.67bc 13.67bc 5.67d
22.33b 15.33cd 29.67a 29.33a 18.00bc 30.67a 11.33d
24.33b 19.67b 31.67a 32.00a 22.00b 32.33a 10.00c
24.67bc 26.33b 38.33a 34.67a 28.67b 34.00a 18.00c
13.67b 13.33b 27.00a 17.33b 13.67b 23.33a 10.67b
20.33a 13.67b 25.33a 23.00 10.00b 23.33a 7.67c
20.00b 19.00b 33.33a 30.00a 16.33b 29.00a 9.00c
14.33a 8.33b 17.33a 13.00ab 11.00ab 13.67ab 8.67b
17.67ab 12.00bc 19.67a 20.67a 12.33b 20.00a 6.33c
18.67bc 17.67c 27.00a 24.33ab 18.33bc 19.67bc 10.33d
df 8 6 48
FPr (2008) <0.001 <0.001 <0.001
PD Variety PD Variety
Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
df 8 6 48
FPr (2009) <0.001 <0.001 0.200
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U. Zakka et al. / Journal of Stored Products Research 60 (2015) 31e35
Table 4 Mean weight loss (g) in maize grains infested by S. zeamais in different varieties under different harvest times and different planting dates as a management technique against S. zeamais infestation. Treatment (planting date and harvest time) Variety 2008 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 2009 ACR.97 TZL COMP.1-W ADV.NCRE-STR AKPARIKE BENDE BG 97 TZE COMP.3XL OGBIA MUNO TZL COMP.4C2 LSD (P 0.05) PD Variety PD Variety
PD1HVT1
PD1HVT2
PD1HVT3
PD2HVT1
PD2HVT2
PD2HVT3
PD3HVT1
PD3HVT2
PD3HVT3
2.16ab 1.89b 1.10b 1.03b 2.29ab 3.99a 1.02b
2.38a 2.27a 1.08a 1.42a 1.44a 1.95a 2.16a
1.63ab 1.25ab 2.20a 1.59ab 1.52ab 1.46ab 0.90b
1.25ab 1.77ab 0.95b 1.32ab 1.92ab 2.18a 1.04ab
1.39bc 2.20a-c 1.49bc 1.29bc 2.81ab 0.99c 3.24a
3.54a 2.04a 2.05a 1.62b 1.23b 0.95b 0.85b
1.36b 2.19b 1.28b 0.75 1.81b 3.17a 0.91b
2.06a 1.90a 1.31a 1.41a 2.23a 1.59a 0.79a
0.80b 2.47a 1.25ab 1.20ab 1.90ab 1.76ab 0.99ab
3.24a 1.89b 3.07a 3.18a 2.96a 3.54a 0.66c
1.17b 1.21b 1.48a 1.79a 1.11b 2.16a 0.92b
3.03a 2.25a 2.71a 3.02a 2.44a 3.07a 0.77b
2.09bc 1.73cd 2.89ab 2.66ab 1.70cd 3.36a 1.04d
1.46a-c 1.25b 2.02ab 2.15a 1.35bc 1.43bc 0.84c
1.89ab 2.01a 2.70a 2.71a 2.32a 2.61a 0.98b
2.17b 1.20c 3.54a 3.16a 2.07b 3.48a 0.94c
1.60a 1.18ab 1.98a 1.77a 1.17ab 1.63a 0.37b
3.04a 1.69b 2.05b 2.71ab 2.58ab 2.49ab 0.53c
df 8 6 48
FPr (2008) 0.687 0.008 0.045
PD Variety PD Variety
df 8 6 48
FPr (2009) <0.001 <0.001 0.14
Means with the same letters in the same column are not significantly (P 0.05) different by StudenteNewmaneKeuls test.
single harvest when all the cobs are completely dry and when there is greater pressure on labor. 4.2. Effective planting time as a tool in mitigating maize weevil attack in stored maize The results suggest that planting maize early (17 October) may predispose the crops to the peak of insect abundance and planting maize around 1 November could be an appropriate planting date of maize to significantly reduce weevil infestation in the study area. Tolerance and resistance also include the ability of the crop to escape invasion or the peak period of damage. If this strategy is adopted it would ensure a relatively pest-free maize in store. This finding concurs with that of Sastawa et al. (2002) who recorded a significantly higher percentage of stem borers in millets sown in the Sudan savanna on 5 August than those sown earlier on 14 July, 21 July and 28 July. Lale and Sastawa (2000) reported a decrease in infestation and damage with delayed sowing and confirmed that head miners became less important as the season advanced and concluded that early sowing of millet causes the coincidence of the heading of these millets with the period of peak activity of the beetles. Ajayi (1990) however, found that early sown millet suffered less stem borer damage than late-sown millet in the Nigerian Guinea savanna. The success of phenological asynchrony as a method of pest management is however dependent, to a large extent, on the nature of the agroecology in which the crop is cultivated; maize is cultivated entirely under rain-fed conditions and the availability of rain determines when cultivation can commence and consequently when harvesting could be done. The integration of planting date with other cultural methods and varietal resistance as a means of controlling S. zeamais infestation is a follow-up on similar work by Lale and Sastawa who reported that by adjusting the planting date of cereal crops damage by meloid beetles was greatly reduced. Other studies on the technique of modifying planting date include those of Nwanze (1997) and Sastawa et al. (2002); in each of these studies, the use of resistant cultivars and manipulation of planting date were reported to be effective methods for the management of stem borers and
head miners in cereal crops. Sastawa et al. (2002) concluded that the method is cost effective from the farmers' point of view and is likely to be adopted easily by subsistence farmers. Acknowledgment The authors would like to thank AAU (pc/6) for funding the work and IITA Ibadan Nigeria for providing the improved varieties used in the studies. The comments by two anonymous reviewers towards improving the quality of this paper are acknowledged. References Ajayi, O., 1990. Possibilities of integrated control of millet stem borer, Acigona ignefusalis Hampson (Lepidoptera: Pyralidae) in Nigeria. Insect Sci. Appl. 2, 109e117. Akob, C.A., Ewete, F.K., 2007. The efficacy of ashes of four locally used plant materials against Sitophilus zeamais (Coleoptera: Curculionidae) in Cameroon. Int. J. Trop. Insect Sci. 27, 21e26. Bergvinson, D.J., 2000. Storage pest resistance in Maize. Maize Res. Highlights 1999e2000. Caneppele, M.A.B., Caneppele, C., Lazzari, F.A., Lazzari, S.M.N., 2003. Correlation between the infestation level of Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae) and the quality factors of stored corn, Zea mays L. (Poaceae). Rev. Bras. Entomol. 17, 625e630. Caswell, G.H., 1970. The storage of cowpea in the northern states of Nigeria. Proc. Agric. Soc. Niger. 5, 4e6. Compton, J.A.F., Flovo, A., Ofosu, A., Agbo, B., 1998. The modified count and weight method and improved procedure for assessing weight loss in stored maize cobs. J. Stored Prod. Res. 34, 277e285. Enobakhare, D.A., Law-Ogbomo, K.E., 2002. Reduction of post harvest loss caused by Sitophilus zeamais (Motsch) in three varieties of maize treated with plant products. Post Harvest Sci. 1, 1e6. Gomez, K.A., Gomez, A.A., 1983. Statistical Procedures for Agricultural Research, second ed. In: An International Rice Research Institute Book Wiley-Interscience Publications, New York. ICAR, 2006. Handbook of Agriculture, fifth ed. Indian Council of Agricultural Research, Krishi Anusandhan Bhavan, New Delhi. Kabeh, J.D., Lale, N.E.S., 2004. Effect of Pre-harvest sprays of neem (Azadirachta indica A. Juss) seed products and pirimiphos-methyl and harvest time modification on infestation of cowpeas by storage bruchids in the field and store in Maiduguri, Nigeria. Niger. J. Entomol. 21, 104e116. Karaya, H., Njoroge, K., Mugo, S., Nderitu, H., 2009. Combining ability among twenty insect resistant maize inbred lines resistant to Chilo partellus and Buseola fusca stem borers. Int. J. Plant Prod. 3, 115e126. Katinila, N., Verkuijl, H., Mwangi, W., Anandajayasekeram, P., Moshi, A.J., 1998. Adoption of Maize Production Technologies in Southern Tanzania. Mexico, D.F.:
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