The Colorado potato beetle is the most economically significant pest of potatoes in our
country and worldwide. Its larvae and adultbeetles feed on potato leaves, which affects
the yield of tubers. The primary method of reducing the damage caused by the
Colorado potato beetle in the past, and also today, has been the use of chemical plant
protection products. However, due to the development of resistance to insecticides
from various chemical groups, there is an increasing trend in seeking alternative
methods of control. In a study conducted from April to August 2022 at the Field
Laboratory of the Biotechnical Faculty in Ljubljana, we examined the effectiveness of
five inert powders (zeolite, silica sand, diatomaceous earth, wood ash, powdered
leaves of common tansy) on different developmental stages of the Colorado potato
beetle (egg masses, younger larvae [L1-L2], older larvae [L3-L3], adult beetles). We
also included a negative control where no potato protection measures were applied and
a positive control where the plants were sprayed with the product Laser Plus
(spinosad). We assessed the percentage of defoliation of the potato plants and the yield
of tubers. The results showed that spinosad and wood ash were most effective in
suppressing younger larvae. Spinosad and zeolite were the most effective in
controlling older larvae and adult beetles. We found that wood ash and zeolite possess
certain insecticidal properties, suggesting that they could be used as additional
methods for the control of the Colorado potato beetle in the future.
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