The efficacy of some natural chemical formulations against the hibiscus mealybug, maconellicoccus hirsutus, green, and its natural enemies in the laboratory and field in Egypt

The hibiscus mealybug, Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) is an important pest on grapevine, guava, soybean, peanut and other plants in various locations in Egypt. In addition to debilitating the host plant due to the loss of sap, the resulting honeydew becomes covered in a thick mat of sooty mould, severely reducing respiration and photosynthesis. This paper presents the results of laboratory and field tests on the effect of natural compounds (Biofly and NeemAzal) and the formulated compounds (Super Mesrona oil and Sumithion) on M. hirsutus and its parasitoids and predators. The laboratory tests indicated that the effect of Sumithion on the mealybug and its natural enemies ranged from 58-98%, Biofly from 15-80%, Super Mesrona oil from 24-98% and NeemAzal from 17-73%, respectively. For the field tests the results indicated that Biofly gave moderate results against nymphs of M. hirsutus, with mean mortality for the two years of 41 and 36% after 3 days, 55 and 51% after 7 days and 58 and 53% after 15 days, while the parasitoids Anagyrus kamali and A. pseudococci (Hymenoptera: Encyrtidae) and Allotropa mecrida (Hymenoptera: Platygastridae) had mortalities of 61 and 48%, 66 and 59%, 55 and 47% respectively for the same periods in the 2 years. The predators Scymnus seriacus (Coleoptera: Coccinellidae) had 50 and 37% mortality and Chrysopa vulgaris aegyptica (Neuroptera: Chrysopidae) had 53 and 41% mortality after 15 days respectively. On the other hand, Sumithion had high efficacy against nymphs of M. hirsutus, with percent reductions of 95%, 96% and 91% for 2008 and 91%, 93% and 88% for 2009. The parasitoids A. kamali, A. pseudococci and A. mecrida had mortalities of 95 and 93%, 90 and 87% and 93 and 90% respectively after 15 days in the two years, while the predators, Scymnus seriacus and Chrysopa vulgaris aegyptica had percent reductions of 88 and 84% and 85 and 82% after 15 days in the 2 years.