Evaluation the toxic effect of some natural alternatives alone and combined with insecticides against the red palm weevil Rhynchophorus ferrugineus (olivier) (Coleoptera: Curculionidae)
2021
Mogahed, M.I.
Experiments were conducted to find out the effectiveness of some biological alternatives (mineral oils and inorganic salts) alone and mixed with pesticides against the fourth larval instar of the red palm weevil Rhcynhophorus ferrugineus (RPW) under laboratory conditions. The larvae were subjected to compulsory feeding on the treated apple fruits with different concentrations (1%, 3%, 5%, 7.5% and 10%) of the tested compounds. The results showed that in the case of forced feeding of red palm weevil larvae R. ferrugineus(RPW) on apple fruits, which were injected with concentrations of 7.5 and 10% of the inorganic salts solution, the treated larvae died in percentages between 20 and 24%. The treatment with mineral oil,caused larval mortality ranged from 80 to 96%. While the treatment with the insecticide (Cydial L), led to larval deaths in percentages ranging between 92 and 100%. As for the compulsory feeding of RPW larvae on the apple fruits treated with the binary mixture (salts + oil) at concentrations of 7.5 and 10%, it caused larval mortality percentages ranging between 64 and 76%. The binary mixture (salts + pesticide), it resulted in mortality of the treated larvae, with percentages ranging from 64 to 88%. The larvae that fed on apple fruits treated with the binary mixture (oil + pesticide) were killed in proportions ranging from 92 to 100%. In the case of forced feeding of red palm weevil larvae (4th instar) on injected apples at a concentration of 7.5 and 10% of the triple mixture (salts + oil + insecticide), the larval mortality rates were 88 and 100% respectively, compared to the control group. The triple mixture of the tested materials with a concentration of 10% is the best against RPW larvae followed by a concentration of 7.5% of the same mixture.
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