HESSIAN FLY (DIPTERA, CECIDOMYIIDAE) CONTROL BY COMPRESSION OF HAY FOR EXPORT TO JAPAN

Laboratory tests showed that significantly more pressure is required t o destroy Hessian fly, Mayetiola destructor (Say), puparia with a volu me of greater-than-or-equal-to 4.0 mm3 than puparia with a volume of l ess-than-or-equal-to 3.4 mm3. About 0.21 kg/cm2 of pressure destroyed all puparia. Compression of hay in commercial compressor with 42 or 72 kg/cm2 of pressure caused significant reductions in survival of Hessi an fly puparia to the adult stage compared with the controls in standa rd bales of timothy, Phleum pratense; alfalfa, Medicago sativa; oat, A vena sativa; Sudan grass, Sorghum bicolor sudanensis; Bermuda grass, C ynodon dactylon hays; and rye straw, Secale cereale. Mortality ranged from 75.1 to 95.4% and was significantly increased by 72 versus 42 kg/ cm2 of pressure on the bales. Compression with 42 or 72 kg/cm2 of pres sure showed the same level of control in the four comers and middle po sitions of the front, middle, and back sections of the bale except tha t fewer insects survived to the adult stage in the middle position of the bale when compressed with 72 kg/cm2 of pressure. Compression of ha y has potential as a single quarantine treatment for hav exported to J apan.