RESPONSE OF GREEN STINKBUG Nezara viridula (LINNAEUS), TO THE ACTIVITY OF ENTOMOPATHOGENIC FUNGI Beauveria bassiana AND Metarhizium anisopliae

Abstract

Greenbug Nezara viridula L. have wide host range more than 30 families and feed on all parts of plant causing high economic damage. Also, it can transmit plant pathogens like bacteria and fungus. Laboratory bioassay of the two entomopathogenic fungi; Beauveria bassiana and Metarhizium anisopliae were tested against N. viridula adult and evaluated their effect of some biological aspects after 24 , 48 and 72 hours from treatment with 107 spores/ml. Result revealed that M. anisopliae treatment had higher activity than B. bassiana treatment. The LC50 values were 1.4x106 and 2.05x107 spores/ml, respectively and the LT50 values were 4.47 and 5.29 days, respectively. Results obtained showed that M. anisopliae caused decrease in each total protein, carbohydrates and lipids contained than B. bassiana . In case of M. anisopliae treatment the mean of total protein content was 19.67, 15.6 and 19.77 mg/g.b.wt after 24, 48 and 72 hours, respectively. However in case of B. bassiana mean of total protein , content recorded 20.83, 24.33 and 25.67 mg/g.b.wt after 24, 48 and 72 hours, respectively whereas the untreated check was 27.3 mg/g.b.wt. The mean of total carbohydrates was 16.63 for the check untreated and recorded 12.47, 10.9 and 12.5 mg/g.b.wt in case of M. anisopliae treatment while these values were 15.3, 16.27 and 16.27 mg/g.b.wt after 24, 48 and 72 hours, respectively in case of B. bassiana . Total lipids recorded highly reduction in case of M. anisopliae content which being were 5.3, 4.63 and 5.1 mg/g.b.wt after 24, 48 and 72 hours compared with 8.63 mg/g.b.wt of untreated. While total lipids showed slight significant decrease after 24 hour in case of B. bassiana treatment and no significance after 48 and 72 hours which recorded 6.73,7.93 and 8.7 mg/g.b.wt, respectively. M. anisopliae treatment caused higher reduction in trehalase activity of N. virdula adults after 24, 48 and 72 hours where the activity levels were 489.67, 390.67 and 161.33 ug glucose/min/g. b. wt, respectively than B. bassiana where the enzymatic activity recorded 273.67, 359 and 506.33 ug glucose/min/g. b. wt, respectively. On the other hand, treatment with M. anisopliae, induced higher reduction in invertase activity for N. virdula after 24, 48 and 72 hours where the enzymatic activity exhibited 401.33, 304 and 258.67 ug glucose/min/g. b. wt, respectively compared with B. bassiana ( 360, 383.67 and 412 ug glucose/min/g. b. wt, respectively). It could be concluded that M anisopliae showed more virulence and its effect on biochemical aspects under the study than that of B. bassiana.