GRANULAR FORMULATIONS OF STEINERNEMA-CARPOCAPSAE (STRAIN ALL) (NEMATODA, RHABDITIDA) WITH IMPROVED SHELF-LIFE

Shelf life (nematode survival) of Steinernema carpocapsae (strain All) nematodes at 21 C in ''Pesta'' granules, made by a pasta-like process , was increased from 8 to 26 weeks by incorporating low concentrations of formaldehyde. Pesta samples containing an average of 427,000 nemat odes/g were prepared with wheat flour (semolina or bread flour), kaoli n, bentonite, peat moss, nematode slurry, and formaldehyde (0-1.4% w/w ) and were dried to a water content of 23.6-26.9%. Nematodes emerged f rom Pesta (S. carpocapsae) granules when placed in water or on moist f ilter paper. Incorporation of 0.2% w/w formaldehyde (nominal; 0.05% by analysis) was optimum for increasing nematode survival in semolina-ba sed Pesta, and also inhibited fungal growth on the granules. Bread flo ur Pesta samples prepared by formaldehyde addition to the nematode slu rry prior to dough preparation, rather than by addition to a mixture o f dry ingredients, had longer shelf life. Nematodes recovered from gra nules made with 0.2% formaldehyde and stored 20 weeks at 21 C caused 1 00% mortality of wax moth (Galleria mellonella) larvae.