Soil application of different neem products to control Ceratothripoides claratris (Thysanoptera: Thripidae( on tomatoes grown under protected cultivation in the humid tropics (Thailand(

Abstract

Ceratothripoides claratris (Shumsher( is an important pest in the tropics, damaging a wide range of crops. Therefore, the effects of soil-applied neem products on C. claratris were investigated on tomatoes (Lycopersicon esculentum( cultivated under tropical conditions in greenhouses in Thailand. NeemAzal-U (NA-U( soil applications resulted in strong systemic effects against C. claratris on young tomato plants when high azadirachtin (AZA( concentrations (400 mg AZA/L( were repeatedly applied. Different application schedules (every second week, weekly, twice a week( as well as organic matter content of typical growing substrates resulted in no significant influence on thrips control. However, plant age did have an influence. The younger the plants were the stronger were the effects after neem soil treatments. A delayed soil application with AZA resulted in increasing thrips population numbers. Of the different Neem products tested, Thai Neem Oil 111 showed the lowest efficiency compared to NA-U and Thai Neem Pellet 222.

Keywords:

• Thrips
• azadirachtin
• soil treatment
• systemic effects

Acknowledgements

We thank Dr E. Hummel of Trifolio-M GmbH (Lahnau, Germany) for providing NeemAzal-U and its blank formulation. The study was funded by the scholarship programme of the German Federal Environmental Foundation (DBU, Deutsche Bundesstiftung Umwelt) and the DFG Research Group FOR 431.