Pyrethrins are a good alternative for controlling rosy apple aphid in apple trees

Rosy apple aphids cause permanent and costly damage to apple trees. A study published in Biological Agriculture & Horticulture has suggested that pyrethrin, organic compounds derived from chrysanthemums, can be used in organic farming as an alternative to neem-derived compound azadirachtin.

• Azadirachtin is the most effective active compound against rosy apple aphids. It is derived from the seeds of the neem tree and is favored by many organic farmers. However, its sale and use are regulated in countries like the U.K.
• The authors conducted experiments in Catalonia from 2005 to 2010. They tested several treatments in autumn (pyrethrins, garlic extract, kaolin, potassium salts of fatty acids, and defoliation) and winter (lime sulfer and paraffin wax) to determine their effects on the aphids and the insects’ eggs.
• They discovered that spraying pyrethrins in autumn was effective in killing oviparae, the female aphids that lay the fertilized eggs over winter and begin the infestation in spring. However, pyrethrins were shown to not cause a knockdown effect on the insects.

The researchers noted that spraying during autumn and killing oviparae successfully kept spring infestation under control.

Learn more about the dangers of chemical insecticides at Chemicals.news.

Journal Reference:

Alins G, Alegre S, Avilla J. ALTERNATIVE TO AZADIRACHTIN TO CONTROL DYSAPHIS PLANTAGINEA PASSERINI (HEMIPTERA: APHIDAE) IN ORGANIC APPLE PRODUCTION. Biological Agriculture & Horticulture. 28 May 2017;33(4):235–246. DOI: 10.1080/01448765.2017.1333454