Drosophila suzukii is an invasive pest of many fruit crops worldwide. Employing the Sterile Insect Technique (SIT) could mitigate D. suzukii population growth and crop damage. This study evaluated the efficacy of SIT on commercial fruit, by (1) validating the quality of irradiated sterile males (male mating competitiveness, courtship, and flight performance) in the laboratory, and (2) assessing population suppression and fruit damage reduction in commercial raspberry fields. Treatment with SIT was compared to the grower’s standard chemical insecticide program throughout the season. The principal metrics of efficacy were trap counts of wild adult female D. suzukii in crops and larvae per fruit during harvesting. These metrics together with monitoring of border areas allowed targeting of high-pressure areas with higher releases of sterile males, to maximise efficacy for a given release number. The sterile male D. suzukii were as competitive as their fertile non-irradiated counterparts in laboratory mating competitiveness and flight performance studies while fertility egg-to-pupae recovery was reduced by 99%. In commercial raspberry crops, season-long releases of sterile males significantly suppressed the wild D. suzukii population, compared to the grower standard control strategy; with up to 89% reduction in wild female D. suzukii and 80% decrease in numbers of larvae per harvested fruit. Additionally, relative fruit waste (i.e., percentage of harvested fruits rejected for sale) at harvest was reduced for early, mid and late harvest crops, by up to 58% compared to the grower standard control. SIT has the potential to provide an effective and sustainable strategy for managing D. suzukii in raspberries, increasing marketable yield by reducing adult populations, fruit damage and waste fruit. SIT could therefore serve as a valuable tool for integrated pest management practices in berry production systems.

By attracting and stimulating feeding on spray droplets, phagostimulant baits provide an opportunity to increase the efficacy of crop protection products against the spotted wing drosophila ( Drosophila suzukii ). Here, we examined the use of a high-sugar, plant-derived bait (ProBandz ^® , PB) in combination with low dose insecticides and an entomopathogenic fungus Metarhizium anisopliae strain 35.79 for control of D. suzukii. We compared the efficacy of treatments in laboratory jar bioassays and in semi-field strawberry experiments using laboratory D. suzukii cultures, and in field strawberry and raspberry experiments on natural D. suzukii infestations. M. anisopliae 35.79 increased D. suzukii mortality in jar bioassays but did not affect oviposition. There was no evidence that combining M. anisopliae 35.79 with PB led to increased efficacy, and in a semi-field experiment this combination led to an increase in D. suzukii larvae in fruit. Deltamethrin in PB droplets was effective in increasing mortality and reducing oviposition in jar bioassays but deltamethrin + PB bait sprays were ineffective in a field raspberry experiment. PB increased the D. suzukii control efficacy of lambda-cyhalothrin in jar bioassays. Low volume bait sprays with 8% of the full field rate of lambda-cyhalothrin in semi-field and field strawberry experiments were as effective in controlling D. suzukii as full rate, high volume insecticide sprays but without causing pesticides residues in the fruit. This work will provide evidence supporting the reduction of dependence and risk of resistance to the two main insecticides used for D. suzukii control: spinosad and cyantraniliprole.

Frankliniella occidentalis is a pest of horticultural crops, including commercial strawberry ( Fragaria x ananassa ). Control is challenging because certain populations are resistant to insecticides and, in strawberry, now relies on the application of biocontrols. However, this approach is not always successful if F. occidentalis populations overwhelm biocontrols. We investigated whether targeted spectral modifications to cladding materials could reduce numbers of F. occidentalis , in strawberry flowers. Five UV‐attenuating plastic‐film materials were tested in three, 6‐week, semi‐field tunnel experiments containing strawberry plants. F. occidentalis were introduced into tunnels from a laboratory culture and subsequent numbers that developed in strawberry flowers were recorded. Limiting UV‐A radiation to the crop significantly reduced the numbers of adult and larval F. occidentalis in strawberry flowers. The numbers of adult (and larvae) in flowers were reduced by 42 (47)%, 54 (41)%, 70 (73)%, and 82 (73)% in UV350, UV370, UV400, and UV430‐attenuating films, respectively, compared with the UVopen (control) film. However, no damage to strawberry fruits was observed regardless of the film treatment. Incorporating UV‐attenuating films as tunnel cladding can suppress F. occidentalis numbers in strawberry. Reducing populations of F. occidentalis in crops is likely to enable the more successful use of other non‐chemical control strategies.