Biocontrol agents of three lepidopterous insect pests on some crops during summer season at Khafr-Elshikh governorate [electronic resource].

Includes reference.

This work was carried out at the farm of Sakha Agricultural Research Station Kafr EI-Sheikh Governorate during two successive seasons, 2005 and 2006 to evaluate the biocontrol agents of the cotton bollworms, Pectinophora gossypiella (Sound) and Earius insulana (Biosd.) as well as the cotton leafworm, Spodoptera littoralis (Boisd.). Six insect predators were recorded, Coccinella undecimpunctata L., Scymnus interruptus Goez, Paederus alfierii Koch. Syrphus spp. Orius spp. and Chrysoperla carnea (Steph). C. undecimpunctata was highly significant in correlation with S. littoralis eggs during June in 2005 and only positive in 2006. Also, C. undecimpunctata was related with S. littoralis larvae during July and August. Highly significant correlation was recorded between both P. alfierii, Ch. carnea, Syrphus spp. and P. gossyhpiella larvae in July and September, respectively. No parasitism was recorded on P. gossypiella and E. insulana larvae in 2005, while only one larva of P. gossypiella was found to be parasitized by Goni02us sp. On August 14 (2006). No parasitism was recorded on S. littoralis eggs during the two study seasons. The overall mean parasitism of S. littoralis was 3.1 and 6.5% in the two seasons, respectively. No entomopathogens were recorded on S. littoralis in the first season, while 5.1 and 15.4% of larval mortality were recorded by bacterial disease and virus (NPV) in 2006, respectively. On maize plants, the overall mean of parasitism on S. littoralis larvae was 0.4% by Bracon parasitoid in 2005 season, while it was 0.6% in 2006 season. The overall means of S. littoralis larval mortality in 2005 was 5.0, 37.3 and 1.1% by bacteria, virus and fungus, respectively. These rates were 3.9, 31.4 and 1.1%, respectively in 2006 season. The highest mortality rates on S. littoralis larvae on soybean was recorded by fungus, Beuvaria basiana in August, where it was 28.3 and 21.6% in the two seasons, respectively, followed by virus and bacteria, 17.9 and 16.6% in 2005 and 22.4 and 18.7% in 2006 season, respectively The overall means with parasitism, bacteria, virus and fungus were 0.7,12.3,14.1,16.3 and 0.8,14.0,17.3,14.8% in 2005 and 2006 seasons, respectively. The highest biomortality agent of S. littoralis larvae on cowpea was bacterial disease, where the overall mean was 14.9 and 14.6% in 2005 and 2006, respectively, while the parasitism and virus were represented with 0.4% of both in 2005 and 0.6 and 0.9% in 2006 season, respectively.

Summary in Arabic.

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