Wheat (Triticum aestivum L.) is an important cereal crop in Pakistan. An aphid complex feeds and signifcantly decrease the grain yield in wheat crop. Field experiment was conducted at NIAB, Faisalabad to evaluate the use of the planting time and the insecticide sprays for managing aphids to avoid losses to grain yield. During the crop season in year 2015-16, wheat variety (Millat 2011) was sown on three planting dates: mid Nov (crop 1), end Nov (crop 2), and mid Dec (crop 3). Trial was laid out in split plot design having three replications. Planting dates were kept in main plots while, insecticide treatments were kept in sub plots. Incidence of aphid population was found in mid January. Three species of aphids: Rhopalosiphum padi (L.), Schizaphis graminum (R.) and Sitobion avenae (F.) were found infesting the wheat crop. At the time of aphid invasion crops were at different growth stages such as 1st node (crop 1), at stem elongation (crop 2) and at end of tiller (crop 3). Maximum aphid infestation was recorded in all crops in the 3rd week of February when crops were at booting stage (crop 1), at flag leaf stage (crop 2) and at 2nd node stage (crop 3). Decline of aphid population was observed in mid March. The highest aphid population was recorded in mid-Dec sown crop followed by end-Nov and mid-Nov sown crops. Two applications of insecticide were used to control aphids during the season. Aphid infestations were higher in untreated plots of mid-Dec sown crop followed by end-Nov and mid-Nov sown crops. Heavy infestation of aphids in untreated plot caused for reduction in plant photosynthetic rate and chlorophyll content. Untreated plots had significantly less grain yield as compared to treated plot in all three crops. Cost benefit ratios were significantly different among three crops as 1:7.3, 1:5.7 and 1:4.8 in mid-Nov, end-Nov and mid-Dec crop, respectively. It is concluded that aphids infestation during the season cause for a decrease of grain yield in untreated plots compared to the treated plots. Early planting gave the highest cost benefit ratio when protected against aphids.
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