An investigation was conducted during 1999-2000 for the study of wheat pests’ phonology in two fields of Sarabyas and Azna villages in Lorestan province based on Hoy and Large methods. Wheat pests according to their importance were Sunn pest Eurygaster integriceps Puton, wheat thrips Haplothrips tritici Kurdjumov, what aphid Schizaphis graminum Rondani in plant sapper guild and cereal leaf beetle Lema melanopa L. in leaf feeder guild, respectively. Among these pests, Sunn pest had the biggest correlation with total infestation in all areas thus being considerd as key pest. Wheat pests feed on different wheat growth stages and injure it. Maximum infestation of sunn pest occurred at wheat maturation stage. The thrips population density was at a high level during growth of stems, flowering and earing stages. Maximum aphid infestation occurred when all spikelets and ears were appearing. Maximum infestation of the cereal leaf beetle occurred when flag leaf was appearing. Population fluctuation studies showed that the pests’ population densities were maximum in mid till late May.
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