Procedures are described for collecting, rearing, shipping, and monitoring the intro- duced ichneumonid, Olesicampe benefactor, a valuable parasite of the larch sawfly, Pristiphora erichsonii

Drooz, A. T

Thompson, L. C

English

Valparaiso University

The Great Lakes Entomologist Volume 19 Number 3 - Fall 1986 Number 3 - Fall 1986 Article 8 October 1986 Collecting, Rearing, Shipping, and Monitoring Olesicampe Benefactor (Hymenoptera: Ichneumonidae), a Parasite of the Larch Sawfly, Pristiphora Erichsonii (Hymenoptera: Tenthredinidae) A. T. Drooz USDA Forest Service L. C. Thompson University of Arkansas Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Drooz, A. T. and Thompson, L. C. 1986. "Collecting, Rearing, Shipping, and Monitoring Olesicampe Benefactor (Hymenoptera: Ichneumonidae), a Parasite of the Larch Sawfly, Pristiphora Erichsonii (Hymenoptera: Tenthredinidae)," The Great Lakes Entomologist, vol 19 (3) Available at: https://scholar.valpo.edu/tgle/vol19/iss3/8 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 1986 THE GREAT LAKES ENTOMOLOGIST 181 COLLECTING, REARING, SHIPPING, AND MONITORING OLESICAMPE BENEFACTOR (HYMENOPTERA: ICHNEUMONIDAE), A PARASITE OF THE LARCH SA WILY, PRISTIPHORA ERICHSONll (HYMENOPTERA: TENTHREDINIDAE) A. T. Droozl and L. C. Thompson2 ABSTRACT Procedures are described for collecting, rearing, shipping, and monitoring the intro­duced ichneumonid, Olesicampe benefactor, a valuable parasite of the larch sawfly, Pristiphora erichsonii. The European ichneumonid, Olesicampe benefactor Hinz, has been a valuable addition to the biological control fauna of the larch sawfly, Pristiphora erichsonii (Hartig), in North America (Muldrew and Ives 1984). Recently several successful relocations have been made to establish O. benefactor in the Nortlleast (Drooz et al. 1985). This paper is written to help others who wish to collect, rear, ship, and monitor O. benefactor. COLLECTING The most convenient way to obtain O. benefactor is to collect its sawfly host, either late instars or prepupae in cocoons. Larvae can be collected by beating infested branches over a white cloth sheet, or infested branches can be cut with a pole-pruner and dropped onto the cloth. Larvae and small branches with foliage should be transported in cloth sacks. Adequate supplies of larch foliage are needed to rear larvae to the cocoon stage. These cocoons should be removed weekly and stored at 15-18°C in barely dampened sphagnum moss. After 30 d they must be chilled at O-SC and held at least 250 d before rearing parasites for release. Rearing larvae is the most expedient way to obtain the parasite when rates of parasitization are high. Collecting cocoons in the field is chancy because there is competition from small, predator mammals. This predation becomes increasingly common as the season progresses, so collecting should be scheduled soon after cocooning occurs, about 1 July in Pennsylvania and 21 July in Minnesota. The sawfly spins its cocoons only in the duff. In sphagnum bogs the cocoons may be found as deep as 20 cm below the surface. Collecting cocoons is time consuming because one needs to sort through large quantities of duff and many empty cocoons from previous years are encountered. Once cocoons have been obtained they should be carried in an insulated container (never leave these insects unprotected from the heat in a vehicle) and taken to a place where it is convenient to sort them by size and condition. Cocoons longer than 9.25 mm are unlikely to contain O. benefactor (Muldrew 1967). Those with visible fungal growth are diseased and should be discarded. IUSDA Forest Service, Southeastern Forest Experiment Station, P.O. Box 70, Olustee, FL 32072. zDepartment of Forest Resources, University of Arkansas, Monticello AR 71655. 1Drooz and Thompson: Collecting, Rearing, Shipping, and Monitoring <i>Olesicampe BenefPublished by ValpoScholar, 1986182 THE GREAT LAKES ENTOMOLOGIST Vol. 19, No.3 25~ VALE I 0 u 0 FEMALE 920 c " -" " .. 15 a. E 0 ';; ~ '0.. 0 "' Z (; a: w ::; w DAY OF EMERGE.NCE Fig. I. Percentage emergence of Olesicampe benefactor adults placed at 18°C on 6 :\lay. after overwintering at O-SC (N 208 1:(,2040). REARING Cocoons should be stored individually to minimize cross contamination with fungi and to isolate them from the cocoon parasite, Tritneptis klugii (Ratzeburg). We used plasric boxes (1.7 by 2 by 2 cm), each with a pinhole in the bottom to admit moisture from white blotting paper dampened with distilled water. (l-oz creamer cups are also suitable. I High relative humidity, but no free contact water, is critical in storage because larch sa\J,ily cocoons desiccate quickly. The boxes were then placed in plastic trays, 50 per tray. The trays of cocoons are stored at 0--5°C, and the blotters kept damp with distilled water. Frequent observations are advisable so that boxes with diseased cocoons can be removed. Olesicampe benefactor parasitizes only first instars. Larch sawfly adults emerge and oviposit over a prolonged period, and O. benefactor adults live for about 30 d. therefore it is best to time the releases for 2--4 d after the earliest sawtly eggs hatch. Generally. this period would be ca. 10 June i  northern Minnesota and ca. 31 May in central Pennsylvania. If this information is unavailable for a particular location. learn when oviposition occurs by looking for the characteristically curled new shoots. Hatch should occur 7-10 d after egg deposition. HANDLING THE PARASITE Adult parasites for release are obtained by moving the presumably pardSitized sawfly cocoons from cold storage t  18°C, Adults begin emergence in 18 d. Approximately 80'* will emerge in the next 7 d (Fig. I). Therefore, allow 25 d lead time at 18=C to meet your scheduled date for releasing the parasites. In a large collection. O. benefactor will continue to emerge for another 30 d. Emergence of most of the males precedes that of the females, Three ichneurnonid species may emerge from the cocoons: the primary parasites. O. benefactor and Mesoleius tenthredinis Morely, and the hyperparasite. ,\Iesochorus globulator (Thunberg) (= dimidiatus Holmgren). These insects are easy to distinguish from one another. The bodies of the parasites are black, whereas that of the hyperparasite 2The Great Lakes Entomologist, Vol. 19, No. 3 [1986], Art. 8https://scholar.valpo.edu/tgle/vol19/iss3/81986 THE GREAT LAKES ENTOMOLOGIST 183 is dark brown dorsally and tan laterally and ventrally. The two species of parasites can be separated by the color of the hind coxae which are black in O. be efactor and amber in M. tenthredinis. Male and female O. benefactor should be caged separately with ample food (40% aqueous honey on disks cut from dental rolls). Females can be identified by their short, external ovipositer sheath. The cages should be kept in the dark at 15°C, and water should be misted or rubbed on the cage screens daily. We had good success with 25 individuals per cage (13 by 18 by 18 em, with wooden sides, 32-mesh screen back, and acrylic sliding door). With this arrangement we could control numbers (501final cage), parasites' interference with one another, and prevention of mating until the parasites were ready for shipping. The parasites are strongly photopositive. It is easy to direct them into one cage with either sunlight or artificial light. First, a small amount of slightly dampened hardwood excelsior is formed into a loose ball in the cage offemales. Fresh food is put on the cage floor and a bright light is applied to the screened end of the females' cage. The cage of females and the cage of males are placed door to door, the doors are opened, and a dark cloth draped over the cages to exclude extraneous light. The males orient quickly to the direction of light and move toward it. When all the parasites are in what was the females' cage, the door is shut. Mating occurs quickly in bright sunlight and then the cage is ready to ship. SHIPPING AND RELEASING Correet authorization for interstate and international shipping is required. Permits for interstate shipment should be requested at least 4 mo in advance. They usually can be obtained through the office of the state entomologist. The permits ultimately are issued by USDA Animal and Plant Health Inspection Service (APHIS) and Plant Protection and Quarantine Programs. International shipping permits have to be requested from officials in the nation receiving O. benefactor. Again, allow ample time to process the request. The cages should be packed in insulated containers with sufficient packs of coolant to keep them cool for the duration of the trip. Adult parasites should be in transit as briefly as possible. Air freight or other special airline service is usually required for 24-h shipment from origin to destination. The recipient should be notified that the package is underway, the name of the shipping service, the bill of lading number, and the estimated time of arrival. The parasites should be released as soon as possible upon arrival. Accurate records should be kept on condition of the package, the sex and number of dead parasites, weather, adequacy of hosts, and observations on the condition of the parasites at release. It is suggested that the location of the liberation site be marked with a painted stake to aid in locating the site for monitoring in subsequent years. Records of the site should contain longitude and latitude, township, range, section, name of nearby community, and other features for identification. MONITORING It is important to monitor the success of the parasite release by rearing future generations of cocooned sawflies. A minimum of 300 cocoons is normally suitable for this purpose. Records from larval rearings or dissections should indicate the progress of the parasite or the need to repeat the introduction. Establishment of O. benefactor should be indicated within 2 yr. Dissection of the sawflies requires a stereomicroscope. single-edge razor blades, a fine forceps, a small bottle of water and medicine dropper, paper tissues, a microscope slide, a block of wood. and dissecting needles. one of which has been altered so that the point is in the handle. A half-spear is handy for scraping the fat body from the inside of the integument. 3Drooz and Thompson: Collecting, Rearing, Shipping, and Monitoring <i>Olesicampe BenefPublished by ValpoScholar, 1986184 THE GREAT LAKES ENTOMOLOGIST Vol. 19, No.3 Cut the end of the cocoon with the razor blade and pull the larva out with forceps. Put the larva on the wood and decapitate it with the razor blade. Carefully, to avoid squeezing, pick up the larva with the forceps and transfer it to your thumb and forefinger. With the blunt-ended dissecting needle on the anal end of the insect, push the larval skin back over the needle until the larva is inside out. Place it on the microscope slide and add two drops of water. Scrape the fat body, guts, etc., into the water with a half-spear, and examine this material at about 15 x with the stereo microscope. Manipulate the mass with the half-spear and a needle to disclose the presence of parasite larvae. Larvae of O. benefactor are hygrophobic and will float free of the host fat body, whereas M. lenlhredinis larvae will not. Descriptions and drawings of these two larval forms are given in Pschorn-Walcher and Zinnert (1971). Use the tissues to clean the slide. ACKNOWLEDGMENTS We appreciate the critical reviews given to the manuscript by H. C. Coppel. Cniversity of Wisconsin, Madison; H. M. Kulman, University of Minnesota, St. Paul; and 1. W Quimby, Pennsylvania Bureau of Forestry Forest Pest Management, Middletown. We also thank C. 1. Lassiter, USDA, Forest Service, SEFES, Olustee, FL, for producing the figure. LITERATURE CITED Drooz, A. T , 1. W. Quimby, L. C. Thompson, and H. M. Kulman. 1985. Introduction and establishment of Olesicampe benefaclor Hinz (Hymenoptera: Ichneumonidae), a parasite of the larch sawfly, Pristiphora erichsonii (Hartig) (Hymenoptera: Tenthredinidae), in Pennsylvania. Environ. Entomol. 14:420-423. Muldrew, 1. A. 1967. Biology and initial dispersion of Olesicampe (Holocremnusl sp. nr. nematorum (Hymenoptera: Ichneumonidae), a parasite of the larch sawtl;.- recently established in Manitoba. Canadian Entomo!' 99:312-321. Muldrew, 1. A., and W. G. H. Ives. 1984. Dispersal of Ole icampe benefactor and Mesochorus dimidiatus in western Canada. Environ. Canada, Canadian For. Serv., North. For. Res. Cent., Edmonton, Alta. Info. Rep. NOR-X-258; 35p. Pschorn-Walcher, H., and K. D. Zinnert. 1971. Investigations on the ecology and natural control of the larch sawfly (Pristiphora erchsonii Htg., Hym.: Tenthredinidae) in central Europe. Part II: Natural enemies: Their biology and ecology, and their role as mortality factors of P. erichsonii. Tech. Bull. Commonw. lnst. Bio!. Contr. 1-1-:1-50. 4The Great Lakes Entomologist, Vol. 19, No. 3 [1986], Art. 8https://scholar.valpo.edu/tgle/vol19/iss3/8

Collecting, Rearing, Shipping, and Monitoring \u3ci\u3eOlesicampe Benefactor\u3c/i\u3e (Hymenoptera: Ichneumonidae), a Parasite of the Larch Sawfly, \u3ci\u3ePristiphora Erichsonii\u3c/i\u3e (Hymenoptera: Tenthredinidae)

https://scholar.valpo.edu/cgi/viewcontent.cgi?article=1576&amp;context=tgle

Collecting, Rearing, Shipping, and Monitoring \u3ci\u3eOlesicampe Benefactor\u3c/i\u3e (Hymenoptera: Ichneumonidae), a Parasite of the Larch Sawfly, \u3ci\u3ePristiphora Erichsonii\u3c/i\u3e (Hymenoptera: Tenthredinidae)

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