Imidacloprid Effects on Probing and Settling Behavior of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera: Thripidae) in Tomato

Abstract

The effects of tomato, Lycopersicum spp., leaves treated with imidacloprid on probing and settling behavior of Frankliniella fusca (Hinds) and Frankliniella occidentalis (Pergrande) were examined using an electrical penetration graph technique and an intact leaf bioassay. For each experiment, thrips were subjected to nontreated plants and plants treated with either of two rates of imidacloprid: 7.81 and 41.55 microg [(AI)] per plant. F. fusca probed less frequently on plants treated with the high rate of imidacloprid compared with the nontreated plants. The duration of F. fusca noningestion probing waveforms and ingestion was shorter on plants treated with the high rate of imidacloprid compared with that on nontreated plants. In contrast, F. occidentalis probed longer and more frequently on plants treated with either the low or high imidacloprid rates compared with nontreated plants. They also ingested more frequently and for longer durations on plants treated with the high rate compared with nontreated plants. The duration and frequency of noningesting probing waveforms were greater on the imidacloprid-treated plants compared with the nontreated plants. F. occidentalis probed and ingested more frequently and for a longer duration than F. fusca on plants treated with the high rate of imidacloprid. F. fusca ingested more frequently and the duration of ingestion was longer than F. occidentalis in untreated plants. F. fusca and F. occidentalis settling behavior differed within the first 30 min in a choice bioassay. F. fusca preferred settling on leaves of nontreated plants, whereas F. occidentalis showed no preference in an intact leaf choice bioassay.

Effect of Transplant Age, Tobacco Cultivar, Acibenzolar-S-Methyl, and Imidacloprid on Tomato Spotted Wilt Infection in Flue-Cured Tobacco

“…IMD affects the settling and probing behavior of thrips. The tobacco thrips (F. fusca), the most important thrips species in tobacco in Georgia, probed for a significantly shorter time on IMD-treated tomato leaves than on nontreated tomato leaves (6). This behavior may also occur on other solanaceous hosts such as tobacco.…”

“…The activation of SAR by ASM may affect both the infection process and the reproduction and movement of the virus in the plant. IMD affects feeding habits of thrips and operates primarily as a feeding deterrent on seedlings (6). The pretreatment with ASM and IMD reduced the percentage of symptomatic plants and increased yields in all 4 years.…”

“…As observed in these trials and other studies, many factors influence the incidence of TSWV in flue-cured tobacco in any given year (4,6,11,12). To be able to compare yields within a year, we included a transgenic K-326 that is not susceptible to TSWV but would be affected by weather and other factors during the growing season.…”

“…It has both systemic and contact activity for the control of sucking insects, including thrips. Joost and Riley (6) found that the tobacco thrips (Frankliniella fusca) reduced probing time on plants treated with IMD and preferred to feed on nontreated plants. IMD acts on the insects in two ways, either killing them directly as a nerve toxin or indirectly when insects avoid feeding on treated plants and starve (13).…”

Management Strategies for Western Flower Thrips and the Role of Insecticides

“…Alternatively, disease reductions observed by Coutts and Jones (2005) may have resulted from sublethal effects of the insecticides on thrips. Imidacloprid was found to actually enhance feeding of western flower thrips on tomato foliage while it reduced feeding by another TSWV vector, Frankliniella fusca (Hinds) (Joost & Riley, 2005). Likewise, the anthranilic diamide, cyantraniliprole, which disrupts insect feeding activity, reduced TSWV transmission by F. fusca, but had no effect on transmission by western flower thrips (Jacobson & Kennedy, 2011).…”