engleski

Effectiveness of new developed natural and safe insecticide formulations against stored product insects

The insecticidal effect of new developed insecticide formulations labelled as Natural P, Inert Natural P and Py EC on Sitophilus oryzae (L.), Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst) have been evaluated on wheat grains. Formulation Natural P contains diatomaceous earth (DE), amorphous silica gel (3%), pyrethrin, flax oil, lavandin essential oil (EO) and un-activated yeast. Formulation Inert Natural P combines DE, amorphous silica gel, lavandin EO and food grade bait whereas formulation Py EC contains pyrethrin, piperonyl butoxide (PBO), flax oil, polysorbate, methyl oleate and amorphous silica gel (5%). DE Celatom® MN-51 was used as a standard insecticide. Inert Natural P and Natural P were applied as dust at four different doses, while Py EC was mixed with water in 4 dilutions containing 0.5, 1.0, 1.5 and 2.0 ppm of pyrethrin a.i. and applied as emulsions on grain by spraying. The LD50 and LD90 values of Inert Natural P were 48.72 and 163.73 ppm respectively for S. oryzae, 15.18 and 177.96 ppm for R. dominica and 115.20 and 171.30 ppm for T. castaneum. The LD50 and LD90 values of Natural P were 53.56 and 97.94 ppm respectively for S. oryzae, 19.47 and 53.05 ppm for R. dominica and 75.40 and 105.60 ppm for T. castaneum. While the LD50 and LD90 values of DE Celatom® MN-51 were 188.55 and 352.79 ppm respectively for S. oryzae, 39.86 and 405.420 ppm for R. dominica and 358.10 and 716.87 ppm for T. castaneum. Comparing with DE Celatom® MN-51 two powder formulations applied at effective concentrations had lower impact on wheat test weight reduction. Applied Py EC at concentration of 2.0 ppm a.i. pyrethrin exhibited 100 % mortality after 2 days of S. oryzae and T. castaneum and after 6 days of R. dominica. In addition, all three formulations caused significant reduction of F1 adults compared to control, providing promising approach of integrated pest management strategy.

stored product insects ; natural substances ; diatomaceous earth ; essential oil ; pyrethrin

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