RESPONSE OF MYZUS PERSICAE (SULZER) TO IMIDACLOPRID AND THIAMETHOXAM ON SUSCEPTIBLE AND RESISTANT POTATO VARIETIES

Among insect pests the Green peach aphid Myzus persicae (Sulzer) is one of the most damaging virulent insect to potato crop. Research experiment was conducted at Research Farm of Khyber Pakhtunkhwa Agricultural University Peshawar, Pakistan during spring 2008 to test two insecticides against Myzus persicae on two potato varieties viz Kuroda and Desiree. The results revealed that both the insecticides Provado 1.6F (imidacloprid) and Actara 25WG (thiamethoxam) significantly suppressed the Myzus persicae population by 74.92 and 67.79%, respectively. Considering the population difference as a parameter, Provado reduced dose was less toxic to Myzus persicae than its labeled dose (4.7%) but it was significantly more toxic than the labeled and reduced doses of Actara by 2.03 and 7.49%, respectively. The population of Myzus persicae on Kuroda control plants was lesser than Desiree by 45.8%. Excluding this difference; the foliar insecticides reduced Myzus persicae on Kuroda more than Desiree by 0.5%. The difference between labeled and reduced doses of foliar insecticides, to reduce Myzus persicae population, on Kuroda was 5.7% and on Desiree it was 4.8%. Comparison of Kuroda and Desiree showed that Kuroda treated with reduced doses of insecticides, except Kuroda treated with labeled doses, had smaller population of Myzus persicae than the Desiree treated with both the doses of insecticides. Significantly highest tuber yield was obtained from plants treated with Provado reduced and labeled doses (both not significantly different). On average, Kuroda yielded significantly higher than Desiree.