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Abstract
Fifteen species of spider belonging to eight different families have been found feeding voraciously on larvae of diamondback moths (DBM), Plutella xylostella; cabbage looper (CL), Trichoplusia nr, army-worms (AW's), Spodoptera latifascia: a pyralid (P), Pilemia periusalis and an unidentified noctuid (N). The population of spiders remained constant in unsprayed fields, ranging from 2/nr of L. atlantica, 4/m2 of L. fusca to 0.08/m2 of others. The spiders were generally most susceptible to diazinon > diaphenthiuron > prophenophos sprays. The spiders showed no preference for the host larvae in multiple-host species diet. Feeding activity that was generally cyclic-intense feeding for a couple days was followed by a similar period of little feeding. The spiders could consume daily about 0.8 to 18.3,0.1 to 1.7 or 0.1 to 1.7 mature larvae of DBM, CLor AW, respectively. Spraying with prophenophos, diazinon and diaphenthiuron reduced the field population of spiders by 43 to 82%, 80 to 100% and 55 to 97%, respectively.