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Moisture requirements of the DD-136 strain of Neoaplectana carpocapsae (Nematoda; Rhabditida) as related to host infection
EXPERIMENTAL
PARASITOLOGY
Moisture
33,
207-211
( 1973)
Requirements of the DD-136 Strain of Neoaplectana carpocapsae (Nematoda; Rhabditida) as Related to Host Infection1 GORDON
Southeastern
E.
MOORE
Forest Experiment Station, Forest Research Triangle Park, North (Submitted
for publication,
Service, Carolina 1 August
USDA, 27709
P.O.
Box
12254,
1972)
MOORE, GORDON E. 1973. Moisture Requirements of the DD-136 Strain of Neoaplectana carpocapsae (Nematoda; Rhabditida) as Related to Host Infection. Experimental Parasitology 33, 207-211. The DD-136 strain of Neoaplectana carpocapsae is capable of continued movement over dry surfaces at 35 and 5 C if relative humidity (RH) ranges above 90%. It can also live in the field on foliage for several hours at night and up to 24 days in bark beetle tunnels in pine bolts. Further nematode research should be directed toward a few insect species where precipitation and RH are suitable for the dispersion of the dauerlarvae. Such areas in the US are located in the Southeast, Northeast, and on the Northwest Coast. INDEX DESCRIPTORS: Neoaplectana carpocapsae (DD-136 strain); Nematodes, moisture requirements; Biological control; Forest insects; Moisture; Relative humidity.
Biological control research frequently employs two or more parasitic species to determine which is most capable of adapting to a set of environmental conditions for controlling a given pest species. Research seeks to determine whether fungus x, parasite y, or nematode z is most efficient. ’ More frequently professional bias, interest, and training cause workers to select presumably useful species within a certain restricted phylum. Some of these parasitic or pathogenic species were discovered as successful in a natural microecological niche here or abroad on related species. Many beneficial species have been appropriated
in hopes that some could become established in a new area. Seldom do we approach biological control from the crop manager’s viewpoint. He is concerned about both time and money and so chooses the simplest and most economical means of pest control. He may consider biological control in certain instances if it has proved successful, but results must be presented so he can adapt them to his problem. Frequently, the missing link in research is that which dibasic knowledge toward viable rects problems. The DD-136 strain of Neoaplectana carpocapsae is a parasitic nematode that acts like a pathogen because bacteria it carries cause a septicemia in the host. It was first found in codling moth larvae in Virginia (Dutky and Hough 1955). The
1 Mention of trade names in this paper is for the benefit of the reader and does not imply endorsement by the USDA to the exclusion of other equally acceptable products. 207 Copyright All rights
@ 1973 by Academic Press, Inc. of reproduction in any form reserved.
208
MOORE
nematode has been evaluated by Dutky (Anon. 1956)) Welch and Briand (1961a), Nash and Fox ( 1969), and Moore ( 1965, 1970). Primarily, research conclusions have recommended against its use because moisture requirements are too great for the dauerlarvae, a stage which moves from host to host. Several workers have elucidated the moisture requirements of the DD-136 nematode. Welch and Briand (1961a) found that 50% drying time was 26 min at 80% and 38 min at 90% relative humidity (RH). B ecause the nematodes frequently enter hosts by ingestion, they must remain viable in the field long enough for several to be consumed. Welch and Briand (1961a) determined that conditions for infection required the Colorado potato beetle, Leptinotarsa decemlineata ( Say), to ingest at least four nematodes. Nematodes they released in the field lived from 15 min to 1 hr, depending upon RH and wind velocity. Moore (1965) and Jaques (1967 j found that all the dauerlarvae died after l-5 hr. Moore (1965) tested the dauerlarvae at 30°C and under 20% RH with negligible air movement. Schmiege (1963) reported that no dauerlarvae survived more than 3.5 hr after release in the field. Jaques (1967) and Welch and Briand ( 1961b) applied DD-136 nematodes to foliage at night because RH is higher then, but neither was more successful than with daytime applications. Schmiege (1963) observed that the normal looping movement of the nematode ceased when water on the leaf surfaces evaporated. The maturing larvae and adults died almost immediately, but he found that dauerlarvae recovered if they were subject to drying for only a short time. Additives have been used in sprays to prolong evaporation (Welch and Briand 196la; Webster and Bronskill 1968; Nash and Fox 1969; and Moore 1970). Webster and Bronskill (1968) were most successful by increasing mortality of the larch sawfly, Pristiphoru erichonii (Hartig ), from 24 to
90% by adding a cross-linked polyacrylamide ( Gelgard M @), polyoxyethylene Polyall fatty acid (Arlantone T@), and mineral wax (Folicate 351@) to the spray solution applied to larch foliage. In other media, the DD-136 nematode was infective for longer periods. Schmiege (1963) found that 30% of the dauerlarvae survived the winter in 0.1% formalin in a plastic bag buried in the ground; he also found that nematode dauerlarvae were infective after being kept for 6 mo in moist soil. Tanada and Reiner ( 1960), Welch and Briand ( 1961b ) , and Jaques et al. (1968) were successful in varying degrees in accomplishing nematode infections of pest insects in the soil or in infested vegetables in the soil. Thus, the dilemma concerning nematode infection of insects is not primarily loss of infectivity through time, but is mortality due to the nematodes being below the critical moisture levels above ground. Reed and Carne (1967) reported a behavioral trait of the nematode in dispersing by bridging and looping makes it more adaptable to moving on the surface of soil or leaves than through the soil. Moore (1965) determined that dauerlarvae of the DD-136 nematode will live until slowly drying soil becomes essentially dry-K@% mortality was reached on the twentieth day of the experiment. MATERIALS
AND
METHODS
Study of movements and longevity. Nealatodes were applied to plant foliage and bark of pine bolts to study movements under two temperature and RH regimes, i.e., in a cabinet at 95 and 100% RH, and 35 and 5 C. Microscope observations were made daily on sprayed bolts and every 10 min on sprayed foliage. Similar tests were also run at ambient temperature-RH in the field during the day and at night. Observations were made every 10 min during the daytime tests, and early in the morning
Neoaplectana
FIG.
1. Areas
in the United
carpocapsae
States
with
mean
after a night application of nematodes to foliage. Adaptability of the DD-136 nematode to geographic precipitation zones. Because dauerlarvae of the DD-136 nematode require high RH during dispersal from host to host, it may be adaptable to only certain areas. National precipitation and humidity patterns were studied, and areas with high precipitation and RH were identified wherein the nematode may have the potential to become established. Also, certain pest insects which are susceptible to the nematode in those regions were listed.
RESULTS Study of movements and longevity. Dauerlarvae of the DD-136 nematode traversed on moist leaf surfaces at the rate of 2 cm/ 15 min. They continued moving after the spray evaporated when held at 95 and 1000/o RH. This indicates that the nematode is capable of dispersing in areas of frequent high RH. However, when nematodes were held at 50-60s RH, the exocutitle or outer sheath began to adhere to the leaf surface soon after the water evaporated. In the laboratory, the nematodes moved equally well at 35 and 5 C on a so-called dry surface at high humidity. In the field, with 50-600/o RH, 5-10s of the dauerlarvae were alive 1 hr after the spray
MOISTURE REQUIREMENTS
annual
precipitation
above
209
45 in. per year.
evaporated. With nighttime applications the nematodes survived several hours, but were all dead soon after daylight the next morning. On sprayed bolts, the nematodes dispersed and entered bark beetle tunnels via the beetle entrance holes. The nematodes lived in the tunnels of slowly drying bolts an average of 15 days. Adaptability of the DD-136 nematode to geographic precipitation zones. Table I lists pests of coniferous and broadleaf trees which are found in zones with precipitation above 45 in./yr, and Fig. 1 outlines those zones. Weather records show that in those areas RH frequently ranges between 80100% and is suitable for the requirements of the nematode dauerlarvae for dispersal. In most of these areas, however, no indigenous insect pests have been tested with the nematode. Negative results have been accumulated in areas with low precipitation even though the high moisture requirements of the nematode are known, For instance, Welch and Briand (1961a) concluded that the nematode was not suitable for use in Ontario. Work by Nash and Fox ( 1969), Moore ( 1970), and Tedders 2 was in or near the 2 Tedders, W. L. Personal communication. Southeastern Fruit and Tree Nut Research Station, Agricultural Research Service, USDA, P.O. Box 87, Byron, Georgia.
210
MOORE TABLE
I
Insects with Potential for Control by the DD-136 Srmatode
Pests
of cottifers Hemlock sawfly 1Iiddletott* Ot,her
sawflies
:\:cot/iprion
tsuyac’ Nor1 heasl
S~otliprion
complex”
Wcs(ertl spt’ttce budworm Chori~s/onc~~rru ocrirlwdolis Freeman” I,ohlolly la&
pine ROSP
Tip molhs
sawfly
15ast Norlhwesl,
:\:codiprion Soltt,h
Rhyucioniu
slq).a
I’:ast,
ant1 West
Pales weevil (Herb&)
Hylobius
l’:xitf
Pest,s of broadleaf Gypsy
tnoth
t,rees Porthrtria
Fall cankerworm taria (Hart%) Large aspett con$icluna
pulps
tlispur
Alsophilu to&ix (Walker)
Other
leaf roller Walket
Nod
he&
pow-
Choris~onc~tra Northeasl
Elm spanworm Ennomos narius (Hiihtter) Codling mot,h Carpocupsu nclla (I,.)* Red-hattded udzltinanu
(L.)a
srtbsiyl,:asl pomo-
Argyrolarnia (:etier:tl
pest it1sect.s Hortse
fly dlccscu tlowstica
Japattese heetle Newman
L.-
(ierteral
I’opi~lircjuponira
s Species or sihlittg I)1 j-1 36 ttematode.
southeastern zone cive to nematode Most work in that has potential for the field.
152st species
fortttd
sttseeptible
10
where climate is conduuse by crop managers. area shows the nematode becoming established in
DISCUSSION
It is valid to conclude that refined field testing of parasites should be restricted to
areas conducive to their life requirements, once they become known. In these areas, the parasites would have the best opportunity to become cstablishetl. I,nter, applications or releases could be extended bcyond the optimal areas until parasites reach their limits of tolerance. Nematodes may be applied with evaporation retardants on foliage and be consumed by pests in the drycst of climates; nevertheless, their potential for becoming indigenous to those areas is almost nil. Furthermore, the cost for producing laboratory cultures of nematodes is such that established methods of crop protection in semiarid zones are likely to continue. One could argue that many insects listed in Table I have only one, or at most two, generations per year and that control with nematodes would not be practical. The nematode is capable of field survival on such insects because it was originally found on the codling moth, an insect with one to three generations per year. Apparently the nematode has the ability to traverse up the tree in spring and to drop with dead insects in the fall to spend the winter in the soil. Dutky (Anon. 1956) reported that the DD-136 nematode could be applied with insecticides and later (Dutky 1967) referred to such trials in the US. In the USSR, pest managers frequently apply a biological agent with an insecticide ( Pristavko 1967 ) . More integrated and biological control methods will likely be sought because of the problem of pesticide residues and the expense of frequent sprays. Good research results, utilizing nematodes in integrated programs, should be available for specialists to recommend. Nematologists should consider nematode parasites for a few selected insects in areas where nematodes may propagate without repeated releases of expensive laboratory reared cultures. Parasitic nematodes could be effectively used in critical areas where pesticides cannot be freely used, such as in orchards, in forested
Neoaplectana watersheds, parks.
along streams,
carpocapsae
and in cities and
REFERENCES ANONYMOUS. cuhr~~
1956. Research
Nematode 4,
on our
side.
Agri-
3-5.
DUTKY, S. R., AND HOUGH, W. S. 1955. Note on a parasitic nematode from codling moth larvae Carpocapsa pomonella ( Lepidoptera, Olethreutidae) . Proceedings Entomological Society of Washington 57, 244. DUTKY, S. R. 1967. An appraisal of the DD-136 nematode for the control of insect populations and some biochemical aspects of its host-parasite relationships. Proceedings of the Joint United States-Japan Seminar on Microbiological Control of Insect Pests, p. 139-140. JAQUES, R. P. 1967. Mortality of five apple insects induced by the nematode DD-136. J0utna2 of Economic Entomology 60, 741-743. JAQUES, R. P., STULTZ, H. T., AND HUSTON, F. 1968. The mortality of the pale apple leafroller and winter moth by fungi and nematodes applied to soil. The Canadian Entomologist 100, 813-818. MOORE, G. E. 1965. The bionomics of an insectparasitic nematode. Journal of the Kansas Entomological Society 38, 101-105. MOORE, G. E. 1970. Dendroctonus frontalis infection by the DD-136 strain of Neopkfana carpocapsue and its bacterium complex. Journal of Nemntology 2, 341344. NASH, R. F., and Fox, R. C. 1969. Field control of the Nantucket pine tip moth by the nema-
M~EXURJZ REQUIREMENTS
211
tode DD-136. Journal of Economic Entomdogy 62, 660-663. PRISTAVKO, V. P. 1967. On the use of entomopathogenic bacteria together with insecticides in the control of insect pests. Entomological Review 46, 443-446. REED, E. M., AND CARNE, P. B. 1967. The suitability of a nematode (DD-136) for the control of some pasture insects. Journal of Inuertebrute Pathology 9, 196204. SCHMIEGE, D. C. 1963. The feasibility of using a neoaplectanid nematode for control of some forest insect pests. Journal of Economic Entomology 56, 427-431. TANADA, Y., AND REINER, C. 1960. Microbial control of the artichoke plume moth, PZatyptiZia car&dactyIa (Riley) (Pterophoridae, Lepidoptera). Journal of Insect Pathology 2, 23O246. WEBSTER, J. M., AND BRONSKILL, J. F. 1968. Use of Gelgard M and an evaporation retardant to facilitate control of larch sawfly by a nematode-bacterium complex. Journal of Economic Entomology 61, 1370-1373. WELCH, H. E., AND BRIAND, L. J. 1961a. Tests of the nematode DD 136 and an associated bacterium for control of the Colorado potato beetle, Leptinotarsu decemlineata ( Say). Canadian Entomologist 43, 759-763. WELCH, H. E., AND BRIAND, L. J. 1961b. Field experiment on the use of a nematode for the control of vegetable crop insects. Proceedings of the Entomological Society of Ontario 91, 197-202.
PARASITOLOGY
Moisture
33,
207-211
( 1973)
Requirements of the DD-136 Strain of Neoaplectana carpocapsae (Nematoda; Rhabditida) as Related to Host Infection1 GORDON
Southeastern
E.
MOORE
Forest Experiment Station, Forest Research Triangle Park, North (Submitted
for publication,
Service, Carolina 1 August
USDA, 27709
P.O.
Box
12254,
1972)
MOORE, GORDON E. 1973. Moisture Requirements of the DD-136 Strain of Neoaplectana carpocapsae (Nematoda; Rhabditida) as Related to Host Infection. Experimental Parasitology 33, 207-211. The DD-136 strain of Neoaplectana carpocapsae is capable of continued movement over dry surfaces at 35 and 5 C if relative humidity (RH) ranges above 90%. It can also live in the field on foliage for several hours at night and up to 24 days in bark beetle tunnels in pine bolts. Further nematode research should be directed toward a few insect species where precipitation and RH are suitable for the dispersion of the dauerlarvae. Such areas in the US are located in the Southeast, Northeast, and on the Northwest Coast. INDEX DESCRIPTORS: Neoaplectana carpocapsae (DD-136 strain); Nematodes, moisture requirements; Biological control; Forest insects; Moisture; Relative humidity.
Biological control research frequently employs two or more parasitic species to determine which is most capable of adapting to a set of environmental conditions for controlling a given pest species. Research seeks to determine whether fungus x, parasite y, or nematode z is most efficient. ’ More frequently professional bias, interest, and training cause workers to select presumably useful species within a certain restricted phylum. Some of these parasitic or pathogenic species were discovered as successful in a natural microecological niche here or abroad on related species. Many beneficial species have been appropriated
in hopes that some could become established in a new area. Seldom do we approach biological control from the crop manager’s viewpoint. He is concerned about both time and money and so chooses the simplest and most economical means of pest control. He may consider biological control in certain instances if it has proved successful, but results must be presented so he can adapt them to his problem. Frequently, the missing link in research is that which dibasic knowledge toward viable rects problems. The DD-136 strain of Neoaplectana carpocapsae is a parasitic nematode that acts like a pathogen because bacteria it carries cause a septicemia in the host. It was first found in codling moth larvae in Virginia (Dutky and Hough 1955). The
1 Mention of trade names in this paper is for the benefit of the reader and does not imply endorsement by the USDA to the exclusion of other equally acceptable products. 207 Copyright All rights
@ 1973 by Academic Press, Inc. of reproduction in any form reserved.
208
MOORE
nematode has been evaluated by Dutky (Anon. 1956)) Welch and Briand (1961a), Nash and Fox ( 1969), and Moore ( 1965, 1970). Primarily, research conclusions have recommended against its use because moisture requirements are too great for the dauerlarvae, a stage which moves from host to host. Several workers have elucidated the moisture requirements of the DD-136 nematode. Welch and Briand (1961a) found that 50% drying time was 26 min at 80% and 38 min at 90% relative humidity (RH). B ecause the nematodes frequently enter hosts by ingestion, they must remain viable in the field long enough for several to be consumed. Welch and Briand (1961a) determined that conditions for infection required the Colorado potato beetle, Leptinotarsa decemlineata ( Say), to ingest at least four nematodes. Nematodes they released in the field lived from 15 min to 1 hr, depending upon RH and wind velocity. Moore (1965) and Jaques (1967 j found that all the dauerlarvae died after l-5 hr. Moore (1965) tested the dauerlarvae at 30°C and under 20% RH with negligible air movement. Schmiege (1963) reported that no dauerlarvae survived more than 3.5 hr after release in the field. Jaques (1967) and Welch and Briand ( 1961b) applied DD-136 nematodes to foliage at night because RH is higher then, but neither was more successful than with daytime applications. Schmiege (1963) observed that the normal looping movement of the nematode ceased when water on the leaf surfaces evaporated. The maturing larvae and adults died almost immediately, but he found that dauerlarvae recovered if they were subject to drying for only a short time. Additives have been used in sprays to prolong evaporation (Welch and Briand 196la; Webster and Bronskill 1968; Nash and Fox 1969; and Moore 1970). Webster and Bronskill (1968) were most successful by increasing mortality of the larch sawfly, Pristiphoru erichonii (Hartig ), from 24 to
90% by adding a cross-linked polyacrylamide ( Gelgard M @), polyoxyethylene Polyall fatty acid (Arlantone T@), and mineral wax (Folicate 351@) to the spray solution applied to larch foliage. In other media, the DD-136 nematode was infective for longer periods. Schmiege (1963) found that 30% of the dauerlarvae survived the winter in 0.1% formalin in a plastic bag buried in the ground; he also found that nematode dauerlarvae were infective after being kept for 6 mo in moist soil. Tanada and Reiner ( 1960), Welch and Briand ( 1961b ) , and Jaques et al. (1968) were successful in varying degrees in accomplishing nematode infections of pest insects in the soil or in infested vegetables in the soil. Thus, the dilemma concerning nematode infection of insects is not primarily loss of infectivity through time, but is mortality due to the nematodes being below the critical moisture levels above ground. Reed and Carne (1967) reported a behavioral trait of the nematode in dispersing by bridging and looping makes it more adaptable to moving on the surface of soil or leaves than through the soil. Moore (1965) determined that dauerlarvae of the DD-136 nematode will live until slowly drying soil becomes essentially dry-K@% mortality was reached on the twentieth day of the experiment. MATERIALS
AND
METHODS
Study of movements and longevity. Nealatodes were applied to plant foliage and bark of pine bolts to study movements under two temperature and RH regimes, i.e., in a cabinet at 95 and 100% RH, and 35 and 5 C. Microscope observations were made daily on sprayed bolts and every 10 min on sprayed foliage. Similar tests were also run at ambient temperature-RH in the field during the day and at night. Observations were made every 10 min during the daytime tests, and early in the morning
Neoaplectana
FIG.
1. Areas
in the United
carpocapsae
States
with
mean
after a night application of nematodes to foliage. Adaptability of the DD-136 nematode to geographic precipitation zones. Because dauerlarvae of the DD-136 nematode require high RH during dispersal from host to host, it may be adaptable to only certain areas. National precipitation and humidity patterns were studied, and areas with high precipitation and RH were identified wherein the nematode may have the potential to become established. Also, certain pest insects which are susceptible to the nematode in those regions were listed.
RESULTS Study of movements and longevity. Dauerlarvae of the DD-136 nematode traversed on moist leaf surfaces at the rate of 2 cm/ 15 min. They continued moving after the spray evaporated when held at 95 and 1000/o RH. This indicates that the nematode is capable of dispersing in areas of frequent high RH. However, when nematodes were held at 50-60s RH, the exocutitle or outer sheath began to adhere to the leaf surface soon after the water evaporated. In the laboratory, the nematodes moved equally well at 35 and 5 C on a so-called dry surface at high humidity. In the field, with 50-600/o RH, 5-10s of the dauerlarvae were alive 1 hr after the spray
MOISTURE REQUIREMENTS
annual
precipitation
above
209
45 in. per year.
evaporated. With nighttime applications the nematodes survived several hours, but were all dead soon after daylight the next morning. On sprayed bolts, the nematodes dispersed and entered bark beetle tunnels via the beetle entrance holes. The nematodes lived in the tunnels of slowly drying bolts an average of 15 days. Adaptability of the DD-136 nematode to geographic precipitation zones. Table I lists pests of coniferous and broadleaf trees which are found in zones with precipitation above 45 in./yr, and Fig. 1 outlines those zones. Weather records show that in those areas RH frequently ranges between 80100% and is suitable for the requirements of the nematode dauerlarvae for dispersal. In most of these areas, however, no indigenous insect pests have been tested with the nematode. Negative results have been accumulated in areas with low precipitation even though the high moisture requirements of the nematode are known, For instance, Welch and Briand (1961a) concluded that the nematode was not suitable for use in Ontario. Work by Nash and Fox ( 1969), Moore ( 1970), and Tedders 2 was in or near the 2 Tedders, W. L. Personal communication. Southeastern Fruit and Tree Nut Research Station, Agricultural Research Service, USDA, P.O. Box 87, Byron, Georgia.
210
MOORE TABLE
I
Insects with Potential for Control by the DD-136 Srmatode
Pests
of cottifers Hemlock sawfly 1Iiddletott* Ot,her
sawflies
:\:cot/iprion
tsuyac’ Nor1 heasl
S~otliprion
complex”
Wcs(ertl spt’ttce budworm Chori~s/onc~~rru ocrirlwdolis Freeman” I,ohlolly la&
pine ROSP
Tip molhs
sawfly
15ast Norlhwesl,
:\:codiprion Soltt,h
Rhyucioniu
slq).a
I’:ast,
ant1 West
Pales weevil (Herb&)
Hylobius
l’:xitf
Pest,s of broadleaf Gypsy
tnoth
t,rees Porthrtria
Fall cankerworm taria (Hart%) Large aspett con$icluna
pulps
tlispur
Alsophilu to&ix (Walker)
Other
leaf roller Walket
Nod
he&
pow-
Choris~onc~tra Northeasl
Elm spanworm Ennomos narius (Hiihtter) Codling mot,h Carpocupsu nclla (I,.)* Red-hattded udzltinanu
(L.)a
srtbsiyl,:asl pomo-
Argyrolarnia (:etier:tl
pest it1sect.s Hortse
fly dlccscu tlowstica
Japattese heetle Newman
L.-
(ierteral
I’opi~lircjuponira
s Species or sihlittg I)1 j-1 36 ttematode.
southeastern zone cive to nematode Most work in that has potential for the field.
152st species
fortttd
sttseeptible
10
where climate is conduuse by crop managers. area shows the nematode becoming established in
DISCUSSION
It is valid to conclude that refined field testing of parasites should be restricted to
areas conducive to their life requirements, once they become known. In these areas, the parasites would have the best opportunity to become cstablishetl. I,nter, applications or releases could be extended bcyond the optimal areas until parasites reach their limits of tolerance. Nematodes may be applied with evaporation retardants on foliage and be consumed by pests in the drycst of climates; nevertheless, their potential for becoming indigenous to those areas is almost nil. Furthermore, the cost for producing laboratory cultures of nematodes is such that established methods of crop protection in semiarid zones are likely to continue. One could argue that many insects listed in Table I have only one, or at most two, generations per year and that control with nematodes would not be practical. The nematode is capable of field survival on such insects because it was originally found on the codling moth, an insect with one to three generations per year. Apparently the nematode has the ability to traverse up the tree in spring and to drop with dead insects in the fall to spend the winter in the soil. Dutky (Anon. 1956) reported that the DD-136 nematode could be applied with insecticides and later (Dutky 1967) referred to such trials in the US. In the USSR, pest managers frequently apply a biological agent with an insecticide ( Pristavko 1967 ) . More integrated and biological control methods will likely be sought because of the problem of pesticide residues and the expense of frequent sprays. Good research results, utilizing nematodes in integrated programs, should be available for specialists to recommend. Nematologists should consider nematode parasites for a few selected insects in areas where nematodes may propagate without repeated releases of expensive laboratory reared cultures. Parasitic nematodes could be effectively used in critical areas where pesticides cannot be freely used, such as in orchards, in forested
Neoaplectana watersheds, parks.
along streams,
carpocapsae
and in cities and
REFERENCES ANONYMOUS. cuhr~~
1956. Research
Nematode 4,
on our
side.
Agri-
3-5.
DUTKY, S. R., AND HOUGH, W. S. 1955. Note on a parasitic nematode from codling moth larvae Carpocapsa pomonella ( Lepidoptera, Olethreutidae) . Proceedings Entomological Society of Washington 57, 244. DUTKY, S. R. 1967. An appraisal of the DD-136 nematode for the control of insect populations and some biochemical aspects of its host-parasite relationships. Proceedings of the Joint United States-Japan Seminar on Microbiological Control of Insect Pests, p. 139-140. JAQUES, R. P. 1967. Mortality of five apple insects induced by the nematode DD-136. J0utna2 of Economic Entomology 60, 741-743. JAQUES, R. P., STULTZ, H. T., AND HUSTON, F. 1968. The mortality of the pale apple leafroller and winter moth by fungi and nematodes applied to soil. The Canadian Entomologist 100, 813-818. MOORE, G. E. 1965. The bionomics of an insectparasitic nematode. Journal of the Kansas Entomological Society 38, 101-105. MOORE, G. E. 1970. Dendroctonus frontalis infection by the DD-136 strain of Neopkfana carpocapsue and its bacterium complex. Journal of Nemntology 2, 341344. NASH, R. F., and Fox, R. C. 1969. Field control of the Nantucket pine tip moth by the nema-
M~EXURJZ REQUIREMENTS
211
tode DD-136. Journal of Economic Entomdogy 62, 660-663. PRISTAVKO, V. P. 1967. On the use of entomopathogenic bacteria together with insecticides in the control of insect pests. Entomological Review 46, 443-446. REED, E. M., AND CARNE, P. B. 1967. The suitability of a nematode (DD-136) for the control of some pasture insects. Journal of Inuertebrute Pathology 9, 196204. SCHMIEGE, D. C. 1963. The feasibility of using a neoaplectanid nematode for control of some forest insect pests. Journal of Economic Entomology 56, 427-431. TANADA, Y., AND REINER, C. 1960. Microbial control of the artichoke plume moth, PZatyptiZia car&dactyIa (Riley) (Pterophoridae, Lepidoptera). Journal of Insect Pathology 2, 23O246. WEBSTER, J. M., AND BRONSKILL, J. F. 1968. Use of Gelgard M and an evaporation retardant to facilitate control of larch sawfly by a nematode-bacterium complex. Journal of Economic Entomology 61, 1370-1373. WELCH, H. E., AND BRIAND, L. J. 1961a. Tests of the nematode DD 136 and an associated bacterium for control of the Colorado potato beetle, Leptinotarsu decemlineata ( Say). Canadian Entomologist 43, 759-763. WELCH, H. E., AND BRIAND, L. J. 1961b. Field experiment on the use of a nematode for the control of vegetable crop insects. Proceedings of the Entomological Society of Ontario 91, 197-202.