Weathering and Chemical Degradation of Methyl Eugenol and Raspberry Ketone Solid Dispensers for Detection, Monitoring, and Male Annihilation ofBactrocera dorsalisandBactrocera cucurbitae(Diptera: Tephritidae) in Hawaii

Abstract

Solid male lure dispensers containing methyl eugenol (ME) and raspberry ketone (RK), or mixtures of the lures (ME + RK), and dimethyl dichloro-vinyl phosphate (DDVP) were evaluated in area-wide pest management bucket or Jackson traps in commercial papaya (Carica papaya L.) orchards where both oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, Bactrocera cucurbitae (Coquillett), are pests. Captures of B. dorsalis with fresh wafers in Jackson and bucket traps were significantly higher on the basis of ME concentration (Mallet ME [56%] > Mallet MR [31.2%] > Mallet MC [23.1%]). Captures of B. cucurbitae with fresh wafers in Jackson and bucket traps were not different regardless of concentration of RK (Mallet BR [20.1%] = Mallet MR [18.3%] = Mallet MC [15.9%]). Captures of B. dorsalis with fresh wafers, compared with weathered wafers, were significantly different after week 12; captures of B. cucurbitae were not significantly different after 16 wk. Chemical analyses revealed presence of RK in dispensers in constant amounts throughout the 16-wk trial. Degradation of both ME and DDVP over time was predicted with a high level of confidence by nonlinear asymptotic exponential decay curves. Results provide supportive data to deploy solid ME and RK wafers (with DDVP) in fruit fly traps for detection programs, as is the current practice with solid TML dispensers placed in Jackson traps. Wafers with ME and RK might be used in place of two separate traps for detection of both ME and RK responding fruit flies and could potentially reduce cost of materials and labor by 50%.

To Catch a Fly: Landing and Capture of Ceratitis capitata in a Jackson Trap with and without an Insecticide

“…Where weekly trap counts have been made, data indicate that including a DDVP vapor strip can lead to initially depressed catches (for about the first week) and then captures return to levels comparable to those from traps without DDVP [ 21 ]. This pattern conforms to the known rapid decrease of DDVP vapors in the field [ 32 ], and reinforces the suggestion that flies are attracted to the lure normally in the presence of DDVP, but perish more frequently before entering the trap, resulting in decreased trap capture efficiency [ 20 , 21 ]. Build-up of insecticide fumes around traps with DDVP has been measured [ 34 ], which is probably responsible for the decrease in trap capture efficiency.…”

“…The effect of DDVP on trap catches has been examined in more detail for Bactrocera fruit flies, where the possibility of repellence by DDVP has also been suggested [ 31 ], though others have found higher trap captures with DDVP than without [ 19 , 32 ] or no significant difference [ 33 ]. Where weekly trap counts have been made, data indicate that including a DDVP vapor strip can lead to initially depressed catches (for about the first week) and then captures return to levels comparable to those from traps without DDVP [ 21 ].…”

Survivorship of male and female Bactrocera dorsalis in the field and the effect of male annihilation technique

“…The results presented here only relate to the effectiveness of MAT against B. dorsalis at the very start of treatment. The amount of ME in the SPLAT spots decreases over time under field conditions, and with it the effect of ‘MAT‐ME saturation’ might also decrease (Vargas et al., ). This might mean that higher application densities are effective over the longer run, though not at the outset, as reduced ME from each point source might reduce the effects of interference that we hypothesize are responsible for the saturation effect.…”

“…This study demonstrates that this topic requires closer attention, and future work should add the effect of uneven spot distribution on survivorship, as real-world programs rarely are able to attain completely even MAT application over a control area, rather place spots according to the location of acceptable public areas such as parks or schools (Gilbert et al, 2013). In addition, it is not clear whether the lower application rate would remain optimal as the MAT spots age; it is possible that, as the amount of attractant coming from each station decreases, the mortality under the high rate would improve and surpass that of a lower density application rate of the same age (Vargas et al, 2015). Based on this study, a lower application density should be considered for managing or eradicating B. dorsalis, but further field studies are needed to confirm that the lower rate remains equally or more effective over weeks.…”

Effect of Lure Combination on Fruit Fly Surveillance Sensitivity

“…Lure combinations offer the prospect of greater surveillance effort being achieved for only a small increase in the cost for the additional lures and no significant increase in labour costs, making such efficiency gains attractive. Recent work in Australia and the USA has sought to trap several species of fruit fly (Diptera: Tephritidae) using various lure combinations 6–10 . There are other examples of combinations of lures for trapping moths 11,12 , beetles 13,14 and species from other insect orders 15 .…”