engleski

The efficiency of azadirachtin and organic fertilizer as environmentally friendly products in pest control

Neem is a long known botanical insecticide whose main active ingredient is azadirachtin. Azadirachtin acts as a regulator of growth and development, and also interferes with feeding and egg laying. The use of various organic fertilizers or reinforcements for plants can also reduce the damages on plants. We investigated the efficacy of azadirachtin (product 'NeemAzal T/S') and product based on organic nitrogen fertilizer ('Boundary SW') against western flower thrips and tobacco flea beetle adults. In laboratory trials, azadirachtin was tested in three doses (1.5 l/ha, 3.0 l/ha, 4.5 l/ha) and fertilizer in a dosage of 3.0 l/ha, in four replicates for both pests, including an untreated control. All variants included ten specimens per replication. For thrips, products were applied by foliar spraying of bean plants, whereas for flea beetles the tobacco plants were treated according to the IRAC No7 method. The test was read every 24 hours for three (thrips) or four (flea beetles) days. The number of dead beetles on insecticide and control was used to calculate the efficacy by using the Schneider- Orelli formula. Besides efficacy, for thrips the damage on leaves and the number of eggs laid were also recorded. The results showed that azadirachtin was not sufficiently effective (66.0%) against western flower thrips adults. However, after 72 hours the highest dose reduced their feeding, and accordingly, the damages on the leaves (4.0%). The same dose also prevented egg laying completely, thus interrupting the life cycle of insect pest. The organic fertilizer showed low efficacy (12.5%) on thrips, but it was effective on thrips feeding and reduced the damages on bean leaves (11.3%). For tobacco flea beetle, the highest dose of azadirachtin showed excellent efficacy (92.1%) after 96 hours. The organic fertilizer was not as effective and showed the efficacy of 59.6%. Considering these results, azadirachtin could be considered as an alternative for chemical insecticides and used for both western flower thrips and tobacco flea beetle control, whereas the organic fertilizer should be investigated further in combination with other biological or chemical products. Secondary effects of some insecticides, such as on feeding and egg laying, should be taken into account in pest control.

efficacy, Epitrix hirtipennis, Frankliniella occidentalis, neem, organic fertilizer

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