The red palm weevil Rhynchophorus ferrugineus (RPW) became the most dangerous insect pests to date palm trees and causes heavy losses to farmers, and due to the negative impact of synthetic pesticides on human health and beneficial organisms…etc in the environment, the use of biological elements was used to treat this insect. Laboratory and field studies were conducted to investigate the potential of two types of fungi Beauveria bassiana and Metarhizium anisopliae on RPW larvae and adults. The biology of red palm weevil were studied on two types of diet, Diet A (sugarcane stems) and Diet B (ground sugarcane + additives). By rearing on Diet A at 27
± 2 °C and 70 ± 5 % R.H. incubation period of eggs was 3.53 days, led to subsequently, to 80% hatching, opposed to 3.62 days with 84% hatchability when rearing on Diet B. the total larval duration lated 103.73 and 98.30 days, respectively, being longer on diet (A) than diet (B). The pupal duration was 17.10 days after larvae rearing on diet (A) and 20.10 days on diet (B). Female and male longevities by rearing on diet (A) was 51.9 and 47.4 days, respectively, opposed to 43.6 and 39.5 days, respectively by rearing on diet (B). That indicated diet (B) proved, generally better for successful rearing of RPW. After treatment of RPW larvae of the 1st, 5th and 10th instars with conidial suspension of Newvar (B. bassiana) and Metmite (M. anisopliae), the recorded mortalities reached 95% in the 1st, 85% in the 5th and 65% in the 10th instar when treated with 1x108CFU’s/100ml from Newvar, while reached to 90% in the 1st, 80% in the 5th and 75% in the 10th instar with 1×109 CFU’s/100ml concentration from Metmite. Where the highest values of LC50 and LC90 were obtained with the 10th instar and the lowest value with the 1st instar i.e. the 10th instar larvae were the highest resistant, while the 1st instar were susceptible. Newvar and Metmite treatment to RPW larvae caused sharp decreases in larval protein content, while caused increases in carbohydrate content. From field treatment, it cleared that the injury recovery rate was 80% for palm trees that were treated with Newvar (B. bassiana) and 60% for trees treated with Metmite (M. anisopliae), i.e. Newvar appeared more efficient than Metmite on RPW stages.
BIOASSAY OF SOME ENTOMOPATHOGENES ON THE RED PALM WEEVIL
