Assessment of the effects of crop injury by blackcurrant leaf midge, Dasineura tetensi (Rubsaamen) (Cecidomyiidae) on yield and growth in commercial blackcurrant plantations

作者：Cross Jerry V^*; Harris Adrian L; Farman Dudley I; Hall David R

来源：Crop Protection, 2016, 82: 51-59.

DOI：10.1016/j.cropro.2016.01.006

• Gall
• Larvae
• Insecticide
• Pyrethroid
• Bifenthrin
• Lambda cyhalothrin
• Ribes nigrum

Sex pheromone trap catches, galling damage, yield and growth were recorded over up to three successive seasons (2010-2012) in large replicated plots treated versus untreated with synthetic pyrethroid (SP) insecticides for blackcurrant leaf midge Dasineura tetensi control in eight established commercial blackcurrant plantations in southern England. The aim was to determine whether or not the current practice of spraying insecticides against the pest in commercial fruiting plantations is justified. In two separate small plot replicated experiments (in 2010 and 2011, respectively) in plantations which had been cut down in the previous winter, galling damage and shoot growth were recorded in the vigorous regrowth in plots treated versus untreated with SP insecticides against 1st, 2nd or both D. tetensi generations. Cutting down bushes to ground level in this way is a common way of regenerating plantations.
In the experiments in the established fruiting plantations, applying sprays of insecticides led to substantial reductions in numbers of adult D. tetensi caught in sex pheromone traps (by 72% on average) and reductions in galling damage (by 75% on average) but did not result in increases in yield or statistically significant increases in shoot growth. Multiple possible mechanisms of yield compensation are discussed. In the experiments in the cut-down bushes where the galling was intense, the D. tetensi damage resulted in severe (59%) stunting and multiple branching of the regrowth which was weak and thin. Sprays against the 2nd generation only partially reduced stunting (to 24%).
The results of this work call into question the current commercial practice of controlling this pest in established commercial plantations with sprays of insecticides: as significant increases in yield or growth did not result in these experiments, the effects of the sprays was largely cosmetic. Further, broad spectrum synthetic pyrethroid insecticides are likely to have persistent adverse effects on the natural enemies of D. tetensi. However, the work showed that control in re-growing cut-down plantations, and by analogy in young establishing plantations, is vital, as well as the value of the D. tetensi sex pheromone traps for timing sprays of insecticides.

• 出版日期2016-4