Effects of different NeemAzal-formulations on apple aphids and Aphis fabae Scop.
Different NeemAzal formulations (containing 1% azadirachtin-A [AZA-A], 51% plant oils) proved to be effective aphicides in laboratory and field trials in south-western Germany. NeemAzal sprays on broad beans [faba beans] and apple trees resulted in significant reductions in numbers of Aphis fabae and Dysaphis plantaginea, respectively. Results with A. fabae showed that an admixture of plant oil improves efficacy. There are differences between different plant oils and emulsifiers. To test the effect of various formulations and application dates, selected formulations were applied to apple trees on 4 fruit farms in different regions during the red bud stage at a concentration of 20-30 g AZA-A/ha. One treatment took place during full bloom. All treatments controlled D. plantaginea effectively and there were no significant differences between treatments. NeemAzal-T/S applied at a rate of 50 mg/kg AZA-A on potted apple trees resulted in high mortality of the offspring of D. plantaginea after 12 days. This effect was also observed on aphids transferred to trees that were treated 14 days before and exposed to 70 mm rainfall. Translaminar effects could also be shown but there was no evidence for systemic activity of NeemAzal-T/S.