תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםThe Red Palm Weevil (RPW) Rhynchophorusferrugineus (Olivier) (Coleoptera: Curculionidae) is one of the most severe pests of various palm species including dates. The weevils develop within the tree trunk, destroying its vascular system and eventually causing the collapse and death of the tree. This study examined susceptibility of eggs, larvae and adults of RPW to two entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana. Initially, some strains of both fungi were screened for pathogenicity on RPW larvae. The M. anisopliae strains were more virulent than B. bassiana, achieving 100% larval mortality within 6-7 days. Subsequently, most virulent strains of M. anisopliae were tested on eggs and adults. Incubation in substrate treated with M. anisopliae spores, increased egg mortality and reduced the eggs' ability to hatch. The total rate of egg and hatched larvae mortality was 62-70% as compared with 23% in control. Weevil adults were challenged with two types of fungal formulation: dry powder and aquatic suspension. Maximal adult mortality of 85- 100% was achieved in 2 weeks for dry powder formulation and in 4-5 weeks for spore suspension. As a result of decreased longevity, treated females had a shorter oviposition time and three times lower fertility than the control. However, we were unable to prove infection transfer from the females to their progeny. We believe that lack of success was due mainly to a poor attachment of spores to the female's body parts. High susceptibility of eggs and larvae to fungal infection implies that biological control of RPW with an entomopathogenic fungus is possible. However, development of a formulation that improves the transfer of fungal spores from females to the RPW oviposition sites is crucial for successful implementation of entomopathogenic fungi in date plantations. [P]
The Red Palm Weevil (RPW) Rhynchophorusferrugineus (Olivier) (Coleoptera: Curculionidae) is one of the most severe pests of various palm species including dates. The weevils develop within the tree trunk, destroying its vascular system and eventually causing the collapse and death of the tree. This study examined susceptibility of eggs, larvae and adults of RPW to two entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana. Initially, some strains of both fungi were screened for pathogenicity on RPW larvae. The M. anisopliae strains were more virulent than B. bassiana, achieving 100% larval mortality within 6-7 days. Subsequently, most virulent strains of M. anisopliae were tested on eggs and adults. Incubation in substrate treated with M. anisopliae spores, increased egg mortality and reduced the eggs' ability to hatch. The total rate of egg and hatched larvae mortality was 62-70% as compared with 23% in control. Weevil adults were challenged with two types of fungal formulation: dry powder and aquatic suspension. Maximal adult mortality of 85- 100% was achieved in 2 weeks for dry powder formulation and in 4-5 weeks for spore suspension. As a result of decreased longevity, treated females had a shorter oviposition time and three times lower fertility than the control. However, we were unable to prove infection transfer from the females to their progeny. We believe that lack of success was due mainly to a poor attachment of spores to the female's body parts. High susceptibility of eggs and larvae to fungal infection implies that biological control of RPW with an entomopathogenic fungus is possible. However, development of a formulation that improves the transfer of fungal spores from females to the RPW oviposition sites is crucial for successful implementation of entomopathogenic fungi in date plantations. [P]
