Functional and numerical responses of Amblydromalus limonicus and Neoseiulus cucumeris to eggs and first instar nymph of tomato/potato psyllid (Bactericera cockerelli) 

Abstract

The tomato/potato psyllid (TPP), Bactericera cockerelli, is a serious pest of some agricultural and ornamental plants, especially of the Solanaceae family. It has been an invasive species in New Zealand since 2006, heavily impacting the potato and tomato industry. The functional and numerical responses of the phytoseiid predators Amblydromalus limonicus and Neoseiulus cucumeris were examined by offering a range of prey densities (two, four, eight, 12, 16, 20, 24 and 28 TPP eggs or 1 st instar nymphs) and compared on a capsicum leaf disc under 25 ± 1ºC, 85% ± 5% RH and a 14:10 h light: dark (L:D) photoperiod. Both species displayed a type 2 functional response when fed on eggs or 1 st instar nymphs of TPP, indicating an increase in the number of prey killed with an increase in prey population density. The results were analysed by using a logistic regression and Holling disc equation. A. limonicus had a higher attack rate for both eggs (0.05 ± 0.01) and 1 st instar nymphs (0.06 ± 0.01) than N. cucumeris, which had an attack rate of (0.03 ± 0.01) for eggs and (0.02 ± 0.01) for 1 st instar nymphs of TPP. N. cucumeris had a longer handling time for both eggs (3.68 ± 0.67 hrs) and 1 st instar nymphs (2.50 ± 0.79 hrs) compared with A. limonicus, with a handling time of (1.74 ± 0.23 hrs) for eggs and (1.15 ± 0.15 hrs) for 1 st instar nymphs. A. limonicus consistently produced significantly more eggs than N. cucumeris across all densities when fed on either eggs or 1 st instar nymphs of TPP. However, the results showed the lack of numerical response of both predator species to prey density. The stronger functional response of A. limonicus to TPP eggs and 1 st instar nymphs indicates that this species can potentially be a more effective biocontrol agent of TPP than N. cucumeris.

Provisioning predatory mites with entomopathogenic fungi or pollen improves biological control of a greenhouse psyllid pest

“…Although significant reductions of TPP eggs, nymphs, and adults by EPF delayed the establishment of psyllid populations on crops, TPP still decreased the development of bell pepper plant and fruit, because eggs produced by infected females still developed into the next generation and continued damaging plant leaves. Regarding the remnants of TPP on leaf surface, the best‐integrated strategy is the simultaneous release of predatory mites that efficiently consume vulnerable TPP (eggs and first instar nymphs) in a relatively short time, considering the developmental time of TPP eggs and first instar nymphs was only 8 days on bell peppers …”

“…Ten TPP females were released to each caged plant at the start of the trial on 1 December 2017. Three days later, all infected plants were randomly assigned to one of the following treatments (Table ) . For the pollen treatment, 50 mg of T. orientalis pollen were dusted on a 5‐mm piece of 1000 cotton threads/plant and released uniformly on each plant twice per week.…”

“…Several predatory mite species, such as Amblyseius swirskii (Athias‐Henriot) (Acari: Phytoseiidae), Amblydromalus limonicus (Garman & McGregor) (Acari: Phytoseiidae), Neoseiulus barkeri Hughes (Acari: Phytoseiidae), Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), and Anystis baccarum (L.) (Acari: Anystidae) have been identified as potential biological control agents of psyllids . The new associations between predatory mites and TPP have only been studied in New Zealand in the last 3 years .…”

“…Both A. limonicus and N. cucumeris feed on vulnerable stages of TPP, such as eggs and first instar nymphs and have a shorter generation time than A. baccarum . N. cucumeris is already commercially produced in New Zealand as a biocontrol agent, but not A. limonicus . Both these mite species could significantly reduce TPP populations on bell pepper ( Capsicum annuum ) in greenhouse conditions (Patel K and Zhang ZQ, Unpublished data; Kean et al ).…”

“…However, TPP has a short generation time and higher fecundity on solanaceous crops, and it can occur throughout cropping seasons, developing three to seven generations per year . The various developmental stages of TPP show different vulnerability to predatory mites; predatory mites mainly attack TPP eggs and first instar nymphs but cannot suppress the later stages and adults of TPP when their populations maintain high densities. In addition, it is challenging to sustain predatory mite populations on crops when vulnerable life stages of TPP are scarce, or predatory mites have high rates of cannibalism …”