حساسية بعض أصناف القمح للإصابة بالحشرة القشرية الرخوة Exaeretopus tritici (Williams) و مكافحتها بمبيد الكروزر في محافظة نينوى (العراق)

Susceptibility of five wheat varitics (i.e Um Rabcc, Intisar, Abu- Ghraib, Qaruniya and waha) to the infestation of the soft scale insect Exaeretopus tritici (Williams) (Coccidae. Homoptera) and the influence of wheat seeds treatment with Cruiser 350 SL insecticide on the pest were evaluated. Results indicated that Um Rabcc was the most susceptible variety to infestation, whereas the variety Qaruniya was the least susceptible. The relative number of living insects on the untreated plants was more than that of treated plant by 23.45, 11.86, 8.11, 2.28 and 7.19 times, respectively. The insecticide effect started by 4th week of March where a percentage mortality of 61.16% was achieved. The mortality percentage was increased until the 3rd week of April when it reached a maximum of 88.4%. The above wheat varieties treated by the insecticide provided a percentage increase in yield by 3.74, 2.17, 1.99, 1.89 and 2.46 times, respectively, as compared to the untreated control. The treated Qaruniya gave the highest yield with an average of 950 kg per donum. The untreated plants of Um Rabcc gave the least yield of 205 Kg per donum, with highest number of living insects with an average of 72.87 insccts/plant Keywords: wheat, soft scale, insect, chemical control. Iraq.