Steinmehl zur Regulierung des Rapsglanzkäfers Meligethes spp.

Summary

In organic agriculture, treatments with rock dusts for soil amendment, disease prevention, or insect control have a long tradition. Clinoptilolite (a naturally occurring zeolite) was tested against pollen beetle Meligethes spp. in oilseed rape fields in order to find a control strategy compatible with the guidelines for organic agriculture in Switzerland. Dust and spray applications were evaluated in several large-scale field trials from 2008 to 2010. Dust applications using 300-750 kg / ha pulverized Clinoptilolite (particle size <0.1 mm; product Klinofeed, company Unipoint, Switzerland) were applied using a drop-box fertilizer spreader or a Vicon pendulum spreader. For spray applications the same Clinoptilolite (product Klinospray) with a particle size of 0.017 mm was applied at rates of 30 - 50 kg / ha with a wetting agent (Heliosol, 2 l / ha; 600 l waster / ha) using a standard field crop sprayer. Under the dry and sunny weather conditions in 2009 and 2010, the treatments significantly reduced the number of pollen beetles by 50 to 80% until seven days after treatment (BBCH 51-54). Under the rainy weather conditions in 2008, no reduction of pollen beetles was observed. In all experimental years a visibly more intense flowering was observed in the treated plots. Pod setting on the main raceme was significantly increased in the treated plots.