Abstract
In Egypt, strawberry is an economically important crop that has recently been destroyed by Pentodon algerinum, a worldwide polyphagous destructive insect pest. This study aimed to distinguish, for the first time, the histopathological and morphological effects of Spodoptera littoralis Nuclear polyhedrosis virus (SpliNPV) and Pentodon algerinum Nuclear polyhedrosis virus (PNPV) on Pentodon algerinum third instar larvae to confirm their success as safe alternative control agents against this pest. The results showed that PNPV and SpliNPV affected Pentodon larvae by the same effects in causing the following: integument deformation and rupture; the destruction of the hypodermal layer resulting in the inhibition of the process of molting into the pupa stage, reducing pest survival; larva leg corrosion, which prevents its spreading; the rupture of fat bodies, which leads to the loss of stored energetic materials; the distortion of muscle sarcolemma and fibers resulting in weakness and softness; the tracheal cuticular layer destruction, which inhibits breathing; midgut rupture with cells detaching from each other; irregular cytoplasm distribution; the loss of the columnar shape of cells; the appearance of vacuoles between cells, which results in their inability to feed or to digest; the swelling, softness, liquefaction, and, lastly, death of the larva. Thus, PNPV and SpliNPV were effective against the Pentodon larva and caused various physiological changes that disrupted its normal functions, leading to the collapse of its population. Hence, PNPV and SpliNPV can be recommended as eco-friendly safe alternative biological control agents against Pentodon algerinum.
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