Comparative Efficacy of Insecticides on Bactrocera tryoni and Zeugodacus cucumis (Diptera: Tephritidae) in Laboratory and Semifield Trials in Fruiting Vegetables

Abstract

In-field management of Bactrocera tryoni (Froggatt) and Zeugodacus cucumis (French) (Diptera: Tephritidae) in fruiting vegetable crops has relied almost exclusively on organophosphate cover sprays. Laboratory and semifield trials were performed to compare a number of alternative insecticides for efficacy against these species. A novel semifield method was used whereby the insecticides were applied to crops as cover sprays under field conditions, and treated plants bearing fruit were transferred to large cages and exposed to fruit flies. Efficacy was assessed in terms of numbers of pupae developing from treated fruit. A laboratory cage method was also used to assess effects on adult mortality and comparative effects of 1-and 3-d-aged residues. The neonicotinoids clothianidin and thiacloprid were very effective against B. tryoni and Z. cucumis. Clothianidin was the only insecticide other than dimethoate to affect adult mortality. The synthetic pyrethroid alpha-cypermethrin was also very effective, particularly in semifield trials, although higher incidence of aphid and whitefly infestation was observed in this treatment compared to others. Cyantraniliprole was effective against B. tryoni, but less effective against Z. cucumis. Imidacloprid, bifenthrin, spinetoram, and abamectin were all relatively less effective, although all demonstrated a suppressive effect.

Dissipation Rates and Effectiveness of Malathion, Imidacloprid, And Dimethoate at Controlling Asian Citrus Psyllids under Field Conditions

“…The spray application method impacts coverage, − and thus the insecticide concentration measured in leaf samples which could affect the rate constant when concentration-dependent (Table ). Greater tree canopy size and foliage can affect light exposure to leaf samples. ,, Thus, smaller trees, like our younger-aged trees sampled, are more likely to have less shade and moisture on leaves, and higher temperatures due to increased light exposure. This could explain our higher dissipation rates observed when insecticides were applied to younger-aged trees .…”

“…Greater tree canopy size and foliage can affect light exposure to leaf samples. 30,47,48 Thus, smaller trees, like our younger-aged trees sampled, are more likely to have less shade and moisture on leaves, and higher temperatures due to increased light exposure. This could explain our higher dissipation rates observed when insecticides were applied to younger-aged trees.…”

Dissipation and Efficacy of Afidopyropen for Controlling Asian Citrus Psyllids Under Field Conditions

“…This may be due to greater canopy foliage, which can affect light exposure, shade, temperature, and moisture on leaf samples. These are factors known to impact dissipation or degradation observed in the field. , In addition to dissipation, other factors like the insecticide’s mechanism or ACP movement may impact efficacy. For instance, a lack of ovicidal activity may allow for egg hatch after treatment to lead to increased ACP counts; however, reduced egg hatch has been observed after treatments of afidopyropen .…”

Field Tests of Three Alternative Insecticides with Protein Bait for the Development of an Insecticide Rotation Program to Control Melon Flies, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae)

“…Before the introduction of spinosad, malathion was the most common insecticide additive to protein baits due to its low mammalian toxicity, affordable price, and low levels of fruit fly resistance [ 20 ]. Abamectin has fewer negative effects on nontarget insects than organophosphate insecticides [ 21 ] and is effective against Z. cucumis , several Bactrocera and Anastrepha species [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Zeta-cypermethrin has been shown to reduce oviposition by Rhagoletis indifferens on cherries [ 30 ].…”