Neem-Azal T/S to control leafhoppers and aphids in greenhouse sweet pepper and tomato.

Summary

Aphids and leafhoppers can cause heavy damage to sweet pepper (Capsicum annuum) and tomato (Solanum lycopersicum). Neem-Azal T/S was therefore evaluated in greenhouse experiments for leafhopper and aphid control.
In 2005, five organic greenhouse compartments were treated with Neem-Azal T/S (0.2%, 1000-1500 L water ha-1; two treatments on tomato; three treatments on sweet pepper) for control of leafhoppers; four greenhouse compartments were left as untreated controls. Leafhopper flight activity was monitored using yellow sticky traps. Leaf damage was estimated by evaluating the fifth leaf from the top of the plant on 100 plants per plot. Flight activity was reduced by 80% (Abbott’s formula; 11-20 days after the 2nd treatment) to 93% (60-75 days after last treatment). Proportion of damaged leaves was reduced by 79-82%.
In 2006, one half of each of six sweet pepper glasshouse compartments (=replicate) was treated with Neem-Azal T/S (0.3%, 800 L water ha-1; three applications), the other half of each greenhouse remained untreated. The number of aphids was estimated by evaluating the fifth leaf from the top of the plant on 200 plants per plot. Three days after treatment, 303 aphids were counted per 100 leaves on untreated plants, while Neem-treated plants had lower aphid densities (24 aphids on 100 leaves). Significant differences in aphid numbers were observed 7, 14 and 21 days after treatment. Efficacy 21 days after treatment was 97.8% (Abbott’s formula). Rapid aphid development in the untreated control plots led to severe leaf distortion, stunted shoots and fruits covered in honeydew. Treated plots did not show any symptoms of aphid damage.
Neem-Azal T/S was effective against aphids and leafhoppers in greenhouse sweet pepper and tomato production in Switzerland. According to observations of growers and pest management advisors, the combination of Neem-Azal T/S and natural enemies might further improve its efficacy.