The feeding and fecundity of Sitophilus granarius (L.), Sitophilus orvzae (L.) and Rhyzopertha dominica (F.) in wheat grain

J. stored Prod. Res., 1969, Vol. 5, pp. 143-155

Pergamon

Press.

Printed

in Great

Britain.

The Feeding and Fecundity of Sitophilus

granarius (L.), Sitophilus orvcae (L.) and Rhyzopertha dominica (F.) in Wheat Grain ZOFIA Plant

Protection

(First received 16 May,

GOLEBIOWSKA Institute,

Poznan,

Poland

1968, and in final form 9 December, 1968)

Abstract-The amount of food eaten by adults of three species kept on wheat grain was assessed over 30 consecutive days in the laboratory at 28°C and 75 per cent r.h. Studies also covered the number of offspring from beetles which fed for 1,2, 3,4 . . . . 30 days, as well as the length of larval development and the amount of larval feeding. Adults of Sitophilus oryzae fed at the same rate throughout the experiment and laid most of their eggs during the first few days after reaching maturity. S. granarius, however, began to lay the eggs only after several days of intensive feeding, when the feeding rate had decreased. Rhyzopertha dominica also at first ate intensively and later at a decreased rate. They laid most eggs during the first few days, and again in the fourth week. Intensive oviposition was preceded by intensive feeding. The amount of food eaten by larvae and adults, together with the quantity of grain dust produced in relation to the adult’s body weight, indicated that of the three species, R. dominica was the most voracious and destructive.

INTRODUCTION

IT IS NOT easy to assess the damage caused by insects of food stores. The rate of development and of feeding depends on temperature, humidity, the type of food product and the pest density. Because of this it is possible, working with the same species, to obtain very different results. Thus ZACHER (1927) claimed that a single specimen of Sitophibs granarius during its lifespan eats about 1 g of grain. STEFFAN (1963)) however, writes that an average sized adult S. granarius or S. oryzae feeds regularly and that it eats 1 mg of grain daily. Accepting the average lifespan of S. granarius as 150 days, the food consumed by an adult would total 150 mg; even adding to this about 30 mg of food consumed by a larva (HURLOCK, 1965), the total would still be considerably less than that quoted by Zacher. While studying the damage potential of S. granarius, S. oryzae and Rhyzopertha dominica (GOLEBIOWSKA et al., 1968) the present author made observations on the feeding of beetles on wheat grain and the amount of food taken by larvae at constant temperature and humidity. 143

144

ZOFI.4 &lLEBIOWSW

METHODS

The studies were made at 28 f 1°C and 75 per cent r.h. with winter wheat raised to about 14 per cent moisture content during the previous week. The l-day-old beetles used in these studies came from a mass culture kept at the same temperature and humidity on wheat grain. The amount of food eaten by beetles was assessed over 30 days. For S. ory~ae 120 cultures and for R. dominica 90 cultures were set up, each containing 100 beetles on 100 g of clean wheat without dust. In the case of S. O~,ZWthe beetles were successively removed from 4 cultures each day for 30 days; in the case of R. dominica from 3 cultures during the same period. The removed beetles were examined and the number of dead and living insects was estimated. At the same time the grain and the debris, which included the grain dust and the droppings, were weighed. After the removal of beetles and after the weighing, the grain was left in the same set of conditions as before, in order to observe the emergence of the new generation from any eggs which might have been laid in the meantime. In experiments with S. ovzae, only the clean grain was retained, while with R. dominica the grain debris was also included since it might have contained eggs; this debris is also necessary as a food for the newly emerged larvae of this species. From the moment the first adults appeared the cultures were examined daily, and any new adults were counted and removed. A week after the last adult appeared, the grain and the debris caused by larval feeding were again weighed. Earlier studies with S. grunarius on wheat were done at 24°C and 75 per cent r.h. (GOLEBIOWSKA et at., 1968). These studies covered the daily mortality of adults and the amount of food eaten. They did not include the daily oviposition rate, but figures were obtained for the total progeny produced over 30 day;.

RESULTS

Sitophilus

oryzae L.

The analysis of daily counts showed that the mortality of S. oryzae adults was small, but that it did not occur evenly throughout the experimental period: it was greatest in the second and last weeks. On average, at the end of 30 days, 92 per cent of the beetles were alive (Fig. 1).

80

*

2

*

4

’

68

’

’

10

12 Day

’

14

*

16

’

I8

’

20

*

.22

3

24

8

’

’

26 26 XI

of experiment

FIG. 1. Mortality course of Sito~hiluso’yrac adult6 during 30 days of the experiment in wheat at 28°C and 75 per cent r.h. (the curve wa6 drawn from a daily count of living beetles).

The Feeding and Fecundity of S. granarius, S. oryzae and R. dominica

145

By the 30th day, individuals of the new generation had begun to emerge from the grain undamaged by adults and emergence continued up to the 69th day, i.e. it lasted for 40 days. From the eggs laid by the beetles kept on the wheat for only 1 day, an average of 120 new specimens emerged. Assuming the sex ratio of 1: 1, one female laid on average 2 -4 eggs on the first day. The eggs took a mean of 31.4 days (30-46) to develop into adults. The number of progeny produced by beetles kept in wheat grain 2, 3, 4 . . . . up to 30 days increased (Fig. 2) but at an

600

* ‘;

-

500-

f “0

400

-

300

-

T i? f a

zoo-

0

100 I

2

4

6

6

IO

12

14

16

Doy

FIG. 2.

of

I6

20

22

24

26

28

30

experiment

Oviposition rate of Sitophilus oryzae during the 30 days of the experiment calculated on the number of emerged beetles.

0

2

4

6

6

IO

12

14 Doy

I6

16

20

22

24

26

26

of experiment

Fro. 3. Hypothetical course of daily oviposition of Sitophilus oryzae in successive days of the experiment calculated from the data given in Fig. 2.

ZOFIA GOLEBIOWSKA

146

301

1 1 2 4 6

a

8

a

h

IO 12

f

14 Doy

FIG.

’

16 of

’

I8

0

20

8

22

1

24

0

26

’

28

’

30

experiment

4. The average development time of the new generation of Sitophilus oryzae measured from the date the culture was set up.

30-

26-

z

g8

22.

ICI-

5 s

14-

IO-

6-

Doy of experiment

FIG. 5.

Increase of amount of food eaten per beetle of Sitophilus oryzae during 30 days of the experiment.

The Feeding

and Fecundity

of S. granatius, S. otyae and R. dominica

147

TABLE 1. THE DEVELOPMENT TIME OF THE NEW GENERATION OF SitophilusoryzaeFROM EGGS LAID IN SUCCESSIVE DAYS DURING 30 days OF THE EXPERIMENT AT 28°C AND 75 per cent r.h. IN WHEAT

Time 100 beetles were kept (days)

No. of emerged new adults

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

120 166 192 237 314 347 362 323 364 364 397 364 400 424 433 443 455 447 451 379 474 513 504 515 570 540 564 544 459 559

Length

% Adult emergence

of development (days)

(days)

Mean

Range

30-34 (32)

35-39 (37)

40-44 (42)

45-49 (47)

50-54 (52)

55-69 (57, 60)

31.4 33.2 32.5 32.7 33.4 34.5 34.6 35.6 36.4 35.8 35.5 36.3 36.0 35.9 37.2 37.0 37.3 38-l 37.5 37.8 38.6 39.3 40.5 40-O 40.7 41.7 40.4 41.5 41.4 41.9

30-46 30-52 30-48 30-53 30-45 30-52 30-54 30-55 30-61 30-53 30-61 30-55 30-61 30-67 30-67 30-59 3048 30-68 30-67 30-6 1 30-68 30-68 30-67 30-68 30-68 30-69 30-69 30-69 30-69 30-69

96.9 74.7 84.5 84.5 73.0 59.8 56.5 43.0 11.2 43.1 48.9 41.9 45.6 48.7 42.4 41.8 42.5 38-O 43.4 46.0 39.1 38.7 30.4 34.9 34.0 28.1 32.8 32.3 30.5 28.7

1.2 21.6 14.6 13.3 24.6 32.8 33.9 43.4 37.5 38-l 32.5 35.7 32.0 29.4 28.3 28.5 25.4 25.3 24.6 25.2 25.2 21.4 23.5 19.0 18.1 21.6 23,7 19.6 21.0 21.3

O-4 3.0 0.8 1.9 2.3 6.6 8.0 11.2 17.0 16.3 15.3 17.9 17.7 15.7 16.7 17.6 16-l 17.7 13.1 12.0 14.0 12.2 14.3 14.7 13.4 12.8 11.8 11.9 15.1 12.5

1.5 0.6 0.1 0.2 0.1 0.6 0.8 2.0 2.6 2.4 2.8 4.0 3.8 4.7 8.6 9.5 11.3 12.8 11.9 10.5 12.2 13.1 14.2 12.7 13.9 13.6 12.0 11.5 10.5 13.7

0 0.1 0 0.1 0 0.2 0.8 0.3 1.1 0.1 0.2 0.4 0.8 0.9 2.2 2.3 3.5 4.9 6.1 5.9 7.7 9.4 12.2 11.8 12.5 13.2 10.6 11.0 11.5 10.9

0 0 0 0 0 0 0 O-l

__

0.6 0 o-3 0.1 0.1 0.6 1.8 0.3 1.2 1.3 0.9 0.4 1.8 5.2 5.4 6.9 8.1 10.7 8.1 13.7 11.4 12.9

uneven rate, while the mean period for the development of the adults also progressively lengthened (Fig. 4, Table 1). Most eggs were laid on the first day of the experiment. Subsequently, the oviposition rate decreased. Figure 3 shows the hypothetical course of daily oviposition rate of 100 S. oyzae beetles calcuIated on the number of newly emerged adults in each of 120 cultures. The amount of food consumed by the larvae was calculated by deducting the weight of grain left over after the new generation had emerged from that left by the parent beetles. On average, one larva consumed 10 mg of grain and produced O-690 mg of grain dust. From the second day, S. otyzae adults fed evenly and consumed about 0.490 mg of grain each day (Fig. 5). The weight of a single S. ovzae adult in these experiments was l-374 &O -011 mg (20 determinations with 500 beetles). Thus the weight of food eaten by a larva during its development was 7 - 2 times greater than the weight of an adult beetle; the food taken daily by an adult was equal to 28 per cent of its body weight.

148

ZOPU GOLEBIOWSKA

Sitophilus granarius L. Adults of S. granatiurkept in wheat at 24°C and 75 per cent r.h. for 30 days died gradually (Fig. 6), but their rate of feeding was uneven. At first they ate a lot (about

*c __ 0

2

______----._

___----

-4.

,mg

of dust

________---

4

6

6

10 I2

14

16

16

20

2; 2

24 26 26 30

Day of experiment

FIG. 6. Mortality course of Sitofihi1u.sgranarius adult6 (upper figure) and amount of food eaten (lower figure) during 30 days of the experiment in wheat grain at 24°C and 75 per cent r.h.

l-5 mg daily) ; later the food consumed substantially decreased, only to increase again considerably towards the end of the experiment (Figs. 6 and 7). Comparison of the adults’ feeding pattern during particular days (Fig. 7) with the emergence of the new generation (Fig. 8) indicated that with S. grrztiu the rate of feeding decreased at the time of copulation and of intensive oviposition. On average, most of the new generation adults emerged between 58 and 64 days after the start of the experiment. At 24°C the development of S. granariustakes approximately 40 days (HOWE, 1966), while the beetles need about 8 days to mature (GOLEBIOWSKA, 1952).

The Feeding and Fecundity of S. granutius,S. oryzaeand R. &mtia

FIG. 7. Hypothetical daily food consumption per 100 adults of Sitophirurgranariurin successivedays of experiment in wheat grain at 24°C and 75 per cent r.h.

0 0

0 336 42 48 54 60 66 72 78 84 90 96 102Da 114120 Time for progeny ddopmemt(sincz

begiming of experiment)

FIG.8. The emergence curve for total developmental period of the new generation of Sitophilus granaries from eggs laid during 30 days of the experiment in wheat at 24°C and 75 per cent r.h.

149

150

ZOFIA

GOLEBIOWSKA

Therefore, the largest number of eggs must have been laid between the 10th and 16th day, and it was during that period that the adults’ feeding rate was the lowest. On the average, during its development, one larva ate 30 mg of grain, leaving 5.70 mg of dust. An adult S. granarius on average weighed 2 - 594 f O-012 mg (20 determinations with 500 beetles), or 11.6 times less than the weight of food eaten by the larva. The daily food consumed by a beetle was equivalent to 20 per cent of its body weight. HURLOCK (1965) found that at 25°C 1 larva ate a mean of 28 - 6 mg of wheat grain and the emerged weevil in these conditions weighed 2 - 8 mg. Rhyzopertha

dominica F.

The heaviest mortality during the experiments was shown by the adults of R. dominica: after 30 days only 62 per cent survived (Fig. 9). As with S. oryzae, the

0

B IO 12 14 16 18 20 22 24 26 28 30

246

Day of kperiment

FIG. 9.

Mortality

0 FIG. 10.

course of Rhyzopertha dominica adults during 30 days of the experiment in wheat at 28°C and 75 per cent r.h.

2 4

Hypothetical

6

8 IO 12 14 16 18 20 22 24 26 28 30

mortality

course of Rhytopertha dominica in successive experiment.

days of the

mortality rate was uneven, being highest in the first and the last week. Certain adjustments had therefore to be made in the computations of the amount of food consumed (Fig. 10). As with S. granarius, the adults of R. dominica did not feed evenly. At first they showed a considerable appetite, then for a few days they ate practically nothing at all, until near the end of the experiment, when they again started feeding intensively (Fig. 11). During this time, they produced a great amount of dust, which increased evenly with time (Fig. 10).

No. of emerged new

466 529 587 635 675 731 760 769 874 888 925 903 872 890 992 1020 1045 1050 1170 1247 1422 1495 1568 1600 1560 1552 1560 1594 1691 1505

Time 100 beetles were kent

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 67.9 69.1 68.9 69.9 69.9 71.3 71.5 71.7 72.9 73.0 73.4 72.6 72.1 72.7 72.8 73.1 72.4 72.0 73.8 74.0 74.2 74-3 75.0 75.3 75.7 75.8 75.2 75.6 75.2 75.4

Mean

Length

41- 84 41- 88 41- 88 41- 86 41- 93 41- 93 41- 93 42- 93 41-101 41-100 41-102 41-102 41-106 41-106 41-107 41-107 41-105 41-105 41-105 41-111 41-112 41-109 41-112 41-112 41-113 41-I 13 41-113 41-114 41-115 41-116

Range

of development (days)

0.6 0.9 1.3 1.7 0.8 I.5 0.6 1.0 0.4 0.8 0.2 0.3 0.7 0.4 0.4 0.6 0.3 0.1 0.7 0.3 0.6

1.4

0.6 0.6 1.0 1.3 1.2 0.3 1.4 0.2

40-53 (46.5)

TABLE 2. THE DEVELOPMENT TIME OF NEW LAID IN ~~~cEssxv~ DAYS DURING 30 days or

1.9 1.1 1.6 0.7 8.0 4.2 4.1 5.3 5.7 2.5 4.3 1.9 0.1 1.3 0.1 0.1 3.9 6.1 2.2 0.2 0.3 0.4 0.3 0.1 0.3 0.1 0.0 0.3 0.2 0.5

54-60 (57.0) 50.5 47.3 49.6 39.5 37.3 34.7 31.4 33.8 25.2 23.4 25.4 26.5 31.9 29.1 24.6 24.9 29.6 33.7 23.8 23.2 17.8 16.2 18.2 18.7 15.1 17.5 17-a 16.2 17.1 19.1

61-67 (64.0) 38.0 34.2 29.6 37.3 27.1 30.0 30.5 26.3 26.7 35.2 25.1 35.5 33.6 34.5 4Q*o 38.2 32.6 27.7 32.0 35.1 41.6 43.4 35.3 31.6 29.9 28.2 33.2 30.8 38.2 33.4

68-74 (71.0) 8.4 14.0 14.5 17.0 19.0 21.2 21.4 22.0 25.1 25.3 28.0 20.5 19.6 20.1 19.8 21.5 15.5 16.3 24.3 25.7 25.2 23.7 26.0 26.7 31.9 30.3 28.8 28.0 24.5 26.2

75-81 (78.0)

“/&Adult emergence

0.9 2.8 3.7 4.2 6.8 8.6 IO.7 11.4 13-o 11.1 13.3 12.0 10.5 11.5 11.4 12.1 13.2 11.7 11.6 12.2 10.9 10.7 15.2 18.7 16.7 17.6 14.2 16.8 13.4 13.4

82-88 (85.0)

(days)

0.6 I.0 0.5 1-O 2.3 I.5 I.9 I.5 I.0 1.3 1.6 1.8 3.3 3.1 4.3 2.8 2.7 3.6 3.8 2.7 4.2 4.5 4.4 5.7 4.2 5.0

0.6 0.4 1.1 0.8 I.1 1.1 0.8 0.7 0.6 0.8 0.9 0.4 0.6 o-9 0.5 0.5 0.5 0.9 0.9 0.9 I.1 0.9

0 0

0

0 0

0 0 0

0 0 0 0

96-102 (99.0)

89-95 (92.0)

GENERATION OF Rhyzopertha dominica FROM THE EGGS AT 28°C AND 75 per cent r.h. IN WHEAT

EXPERIMENT

0.2 0.3 0.2 0.1 0.3 0.2 0.1 0.2 0.6 0.4 0.3 0.6 0.8 0.6 0.6 0.6 1.0 0.9

0 0 0 0 0 0 0 0 0

0

0 0

103-116 (109.5)

152

ZOFIA GoLBBIOwsKA

I iW-

I 0

/

600-

o)

500-

E 2 < e E

400-

0 300-

200-

0

8

IO

12

14

16

18

2U

22

24

26

28

30

Day of experiment

FIG. 11. The amount of food eaten and the amount of dust produced by Rhy.zo@rfhu dominicaadults during 30 days of the experiment in wheat grain at 28°C and 75 per cent r.h. The data for wheat eaten refer to the 100 adults with whom the experiment was started (full line) and to surviving adults (broken line).

In contrast with S;toptCil~ spp. females of R. dominica lay eggs either outside or between the grains. Larvae feed for a time on the grain debris and dust formed by the beetles. Eggs were laid during the first day (3 eggs/female), from which adults emerged between the 41st to 84th day (67 -9 days on average-Table 2). During subsequent days, the number of progeny increased (Fig. 12), but the oviposition rate showed a pattern of four periods: the rate was highest during the first day, then decreased progressively until the 10th day, increased up to the 22nd-24th day, and decreased again near the end (Fig. 13). Comparison of oviposition with the daily feeding rate (Fig. 11) shows that as with S. granarks more intensive egg laying must be preceded by a period of increased feeding. This observation agrees with those of LEPESME (1944), who reported that the females are particularly voracious before egg laying. The development period, even for individuals developing from eggs laid on the Figure 15 shows the average development time for same day, was very variable. the progeny of beetles which have spent periods of up to 30 days in the grain. At a temperature of 28°C the embryo of R. dominica takes 4-8 days to develop (GOLEBIOWSKA, 1962 ; HOWE, 1950). The young larvae feed mainly on the grain debris left over by the beetles, and it is only after the second ecdysis that they are

The Feeding and Fecundity of S. granarius, S. oryzae and R. abminica

Day

FIG.

12.

Hypothetical

0

2

4

ofexperiment

daily food consumption per adult of Rhyzopertha dominica in successive days of the experiment in wheat.

6

8

IO

I2

14

I6

16

20

22

24

26

28

30

Day of experiment FIG.

13. Oviposition rate of Rhyzoprtha dominica during 30 days of the experiment in wheat at 28°C and 75 per cent r.h.

153

154

ZOFIA

GOLEBIOWSKA

40-

% $

30-

75 _i E 1

?O-

IO

O

2

4

6

8

IO

I?

14

16

18

20

22

24

26

28

30

Day of experiment 14. Hypothetical course of daily oviposition of Rhyzopertha dominica in successive days of the experiment, calculated from the data given in Fig. 13. The full line refers to the 100 adults with which the experiment was started and the broken line to surviving adults. FIG.

Day FIG.

15.

The

of ovlposltlon

average development time of the new generation of Rhyzopertha measured from the date the culture was set up.

dominica

able to bite into the undamaged grain. It is therefore probable that the considerable increase in the amount of food consumed after the 24th day (Fig. 11) was due to the simultaneous feeding by the beetles and the larvae which hatched from eggs laid during the first days. On average, during its growth, a larva consumed 12 mg (9-16 mg) of grain, leaving 7 mg (5-10 mg) of grain dust at the same time. A beetle ate 0.325 mg of grain/day, leaving 0 - 025 mg of dust. A freshly emerged beetle weighed l-4035 &O *015 mg (20 determinations with 500 beetles), i.e. the food consumed by a larva was 11.6 times greater, while the daily food eaten by a beetle was equivalent to 31.8 per cent of its body weight.

The

Feeding

and Fecundity

of S. panarias,

S. oryzae and R. dominica

155

DISCUSSION

of According to STEFFAN (1963) an adult of the genus Sitophilus (irrespective species) feeds regularly, consuming about 1 mg of wheat grain daily. In these experiments, at 28°C and 75 per cent r.h., S. or_ytaefed fairly regularly, but ate only 0.490 mg, i.e. about half the amount quoted by Steffan. In earlier investigations (GOLEBIOWSKA et al., 1968) at 24°C in wheat, an adult S. oyzae ate on an average even less, 0 ~400 mg daily. On the other hand, the adults of S. granarius at 24°C showed an uneven appetite, eating at first a lot-about 1.5 mg daily, and practically the average quantity of food ceasing to feed after a few days. In consequence, consumed during the 30 day experiment was less than reported by Steffan. It seems that with S. granarius the reduction of feeding was associated with a period of intensive oviposition. According to Steffan, adults of S. oryzae mature and begin egg laying earlier than those of S. granarius, which at 25°C are ready to lay eggs only after 9 days. HOWE and HOLE (1967) found that at 25”C, S. granarius begins to lay, eggs at the earliest on the 5th or 6th day, and that the peak occurs between the 10th and 30th day. A similar peak occurred in our experiments; egg laying took place mainly between the 10th and 16th day. With S. ovsae, on the other hand, most eggs were laid earlier, agreeing with Steffan’s report. Before egg laying, both R. dominica and S. oryzae fed intensively and broke the grain, thus easing the development of larvae. R. dominica, however, produced more debris and dust, not only through the feeding by adults, but also by the larvae. Thus: while S. oryzae or S. granarius produced 1 l-12 mg of dust throughout their lives, R. dominica gave rise to about 54 mg. Taking into account the weight of food eaten during the larval growth and the ratio of daily food taken by the adults to their body weight, R. dominica appears to be the most \ioracious of the three species considered. REFERENCES BALACHOWSKY, A. S. (1963) Entomologie apPliquba l’agriculture. 1 (2) Coltopteres. Masson et Cie, Paris. GOLEBIOWSKA, Z. (1952) Granary weevil (Calandra granaria L.) morphology, biology, ecology and control. Roczn. Nauk roln.. 64, 137-221. GOLEBIOWSKA, Z. (1962). Contribution to studies on the ecology of the lesser grain borerRhizopertha dominica F. (Col., Bostrichidae). Polskie Pismo ent. (B) 1-2, 39-51. GOLEBIOWSICA, Z., FILIPEK, P. and KRZYMAASKA, J. (1968) The damage potential of S. granarius L., S. o+zae L. and R. abminica F. to grain of wheat and rye. Pr. nauk. Inst. Ochr. Roll. 10, 31-56. HOWE, R. W. (1950) The development of Rhizopertha dominica (F)(Col. Bostrichidae) under constant conditions. Entomologist’s mon. Alag. 86, l-5. HOWE, R. W. (1966) Development period, and the shape of the curve representing it in stored products beetles. J. stored Prod. Res. 2, 117-134. HOWE, R. W. and HOLE, B. D. (1967) The yield of cultures of Sitophilus granarius at 25°C and 70 per cent relative humidity with some observations on rates of oviposition and development. J. stored Prod. Res. 2, 257-272. HURLOCK, E. T. (1965) Some observations on the loss in weight caused by S~~o~~i~usgranarius (L.) (Coleoptera, Curculionidae) to wheat under constant experimental conditions. J. stored Prod. Res. 1, 193-195. LEPESME, P. (1944) Les Coleopttres des den&es alimentaires et des produits industriels entreposes. Encycl. ent. (A) 22, I-330. STEFFAN, J. R. (1963) Les calandres des grains (Sitophilus). In: Entomologie appliqub a l’agriculture (Ed. by BALACHOWSKY, A. S.) 1 (Z), 1070-1099. Die Vorrats-, Speicher- und Materialschadlinge und ihre Bekampfing. ZACHER, F. (1927) Paul Parey, Berlin.