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Insect Pathology Team

Guy MERCADIER, Nicolas CRESPY, Fatiha GUERMACHE
Paul C. QUIMBY (part-time)

 

TRAVEL

 

Guy Mercadier and Chuck Quimby traveled 23-25 February 2000 with Jacques Fargues of INRA and Larry Vaughan of Virginia Tech to Dijon, France, to meet with Alain Durand of INRA and his team in their fermentation laboratory where they have platforms for liquid and solid state fermentation (pilot plant scale). The purpose was to share research information with them and acilitate the initiation of a pilot scale test of liquid fermentation of Metarhizium flavoviride for testing against Schistocerca spp. (locusts) and grasshoppers, with focus in Africa.

The meeting was a success and the project was initiated. This was an activity related to EBCL’s subcontract with INRA. Jacques Fargues of that agency receives funds through Virginia Tech that originate from U.S. AID.

Note: This project was established at EBCL by Dr. Fernando Vega who left EBCL in August 1999; the project has been continued since then by the team listed above. This report includes only information generated by the team after Dr. Vega's departure.

Guy Mercadier: Traveled to Norway in May with Nicolas Crespy, and with Dominique Coutinot to the Republic of Georgia in June. Guy's purpose was to collect Cydia pomonella from traps established earlier by Fernando Vega, Guy, and cooperators.

Planned trips for the rest of the year: It may be necessary to return to Georgia to collect the traps placed there in June and set some new ones for the winter.

RESEARCH IN PROGRESS

 

We are continuing to work on comparing various formulations of Metarhizium spp. in conjunction with the INRA project. INRA is responsible for the testing of environmental resistance and for bioassays against the locusts. We are responsible for comparing media and various additives as they affect shelf life of blastospores under various temperatures. To accomplish this, we have compared additions of sugar, tween-80, glycerol, and water. To do this, we determine colony forming units per gram of formulation. We are also working on various combinations of oil as carriers for application. We have found that a medium developed by Mark Jackson of ARS in Peoria is superior to several others. (This result confirms the early results of Dr. Vega). We have compared various carriers as flocculants for filtration and found that lignin appears to be superior to hydrated silica, and both are superior to water-absorbent starch. The flocculants and the filtration simplify the harvesting procedure in comparison to our earlier methods. We have passed samples of the formulations to Jacques Fargues who is testing the resistance of the blastospores to UV-B and to temperature extremes (45/15° C); Jacques will select the most promising formulations for a limited number of bioassays.

The addition of sugar appears to enhance the shelf life at room temperature (ca. 25° C.) and in the refrigerator (ca. 4° C.); amazingly, Guy Mercadier found that the addition of extra water at 96 hours of fermentation greatly increases the yield in the final 3 days. We do not yet know the reason, but Jacques Fargues speculates it may be dilution of an autotoxin produced by the fungus. Guy Mercadier has also initiated preliminary trials of solid state fermentation and has found good production of conidia with millet or corn or ground corn.

Research is continuing on biological control of Cydia pomonella and Plutella xylostella. Colonies of both are maintained in the laboratory. We have initiated and are maintaining a colony of the nematode, Steinernema carpocapsae on C. pomonella. The source of the colony was infected larvae collected by Dr. Kim Chen in the Jura mountains of Switzerland. We are maintaining a colony of P. xylostella for cooperative research with Alan Kirk of EBCL and Dominique Bordat of CIRAD. We plan to test some of our isolates from various collections against P. xylostella, but until now, Dr. Bordat has had difficulty in maintaining his colony of the target without microsporidial contamination. We are working with him to help resolve that problem.

VISITING SCIENTISTS

 

In February, we were visited by Dr. Larry Vaughan of Virginia Tech, who is the project manager for the U.S. AID-funded project with Metarhizium. We discussed results to date and plans for the future research on the project.

We had a Ph.D. candidate, Jarrod Leland, from Virginia Tech, who worked in our lab and Jacques Fargues' lab on the Metarhizium project for 2 weeks from 1 March 2000 to about 15 March 2000. It was Jarrod who led us to the idea of using lignin as a carrier for the blastospores.

The team from INRA in Dijon, led by Dr. Alain Durand and with Miguel Diez , visited our lab on 6 July 2000 to discuss their results on pilot scale fermentation and make plans for the next phase of the project.

STUDENTS

 

Chloe Tewksbury of Berea College, Kentucky, has spent several days in the insect pathology lab becoming familiar with the procedures used and helping with some routine cfu determinations from petri-dish cultures.

TECHNOLOGY TRANSFER

 

In December 1999, the project transferred approximately 50 isolates of insect pathogens from coffee berry borer (CBB) collected in several African countries (and 29 March 2000 approximately about 100 frozen adults of diseased CBB from Africa and Central America) to Dr. Fernando Vega of ARS, Beltsville, MD.

About 12 May 2000, nine specimens of duplicate parasites and CBB associated insects were sent to Dr. Richard Greene, Acting Deputy Director who passed them on to Dr. Kevin Hackett for further distribution to ARS' Systematics Entomology Lab.

The team also shipped nematodes (Steinernema carpocapsae) from C. pomonella to Dr. Larry Lacey of ARS in Yakima, Washington. The sources were Switzerland (ex. Dr. Chen's collection)- sent 25 October 1999, and Norway (ex. G. Mercadier's collection from 3 sites)- sent 7 June 2000. These nematodes should be cold-hardy from Northern climates, especially Norway, and could perhaps be well adapted to Washington State.

PUBLICATIONS

 

In preparation: Mercadier, G., J. Fargues, F. Guermache, and P.Quimby. 2001. Fermentation and formulation studies toward development of field-ready Metarhizium flavoviride for biological control of pest locusts and grasshoppers. Intended for Biological Control.

FUTURE PLANS

 

We will continue to work with INRA toward development of a field-ready formulation of Metarhizium flavoviride for control of pest Orthoptera. We will continue to work with ARS cooperators in Yakima, Washington on biocontrol of Cydia pomonella and with ARS/CIRAD cooperators on biocontrol of Plutella xylostella. We will initiate work with Dr. Kim Hoelmer and his team on the use of insect pathogens to control Lygus spp.