Use of Fluorescence, a Novel Technique to Determine Reduction in <I>Bemisia tabaci</I> (Hemiptera: Aleyrodidae) Nymph Feeding When Exposed to Benevia and Other Insecticides

Abstract

The sweet potato whitefly, Bemisia tabaci (Gennadius), is an economically important pest in the United States and other countries. Growers in many places rely on the use of insecticides to reduce populations of B. tabaci. However, insecticides may take a few days to cause B. tabaci mortality and some do not reduce feeding before death. Earlier reduction of feeding of whiteflies would decrease the physiological effects on plants, reduce the production of sooty mold and potentially reduce the transmission of viruses. Measuring the reduction in feeding after the exposure of B. tabaci to an insecticide has proven difficult. This series of laboratory experiments demonstrate the usefulness of fluorescence in determining B. tabaci feeding cessation. Fluorescein sodium salt is systemically transported in the xylem from the roots to the plant leaves and absorbed by B. tabaci nymphs feeding on these plants. Nymphs start fluorescing shortly after the cotton plant root system is submerged in the fluorescein sodium salt. Using this novel technique, the effect of three insecticides with different modes of action, cyantraniliprole, imidacloprid, and spirotetramat on B. tabaci was evaluated and compared to determine reduction in feeding. Results indicate that B. tabaci nymphs feeding on a plant treated with Benevia have a significant reduction of feeding when compared with nymphs feeding on plants treated with imidacloprid or spirotetramat. Both Benevia and spirotetramat caused significant nymphal mortality by 48 h after exposure. This novel technique will be useful to demonstrate the feeding cessation or reduction in feeding produced by different insecticides in several sucking insect groups.

Combining Novel Modes of Action for Early-Season Management ofBemisia tabaci(Hemiptera: Aleyrodidae) and Tomato Yellow Leaf Curl Virus in Tomato

“…The same authors (2013b) measured a reduction in the number and duration of probes by Frankliniella fusca (Thysanoptera: Thripidae) feeding on pepper treated with cyantraniliprole. Cameron et al (2013) used fluorescent dye to show feeding reduction on the part of B. tabaci nymphs on cotton treated with cyantraniliprole. In addition, settling and feeding behavior of Diaphorini citri Kuwayama (Hemiptera: Psyllidae) was reduced on citrus treated with cyantraniliprole (Tiwari & Stelinski 2013).…”

Effect of Cyantraniliprole on Feeding Cessation of Q Biotype Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)

“…In a recent study, where fluorescence was used to determine the feeding cessation of B biotype B. tabaci nymphs, plants treated with cyantraniliprole also caused a significant reduction of feeding when compared with nymphs feeding on plants treated with imidacloprid or spirotetramat [34]. Another study showed a reduction in the amount of honeydew produced by B biotype B. tabaci adults in cyantraniliprole treatments equivalent to imidacloprid.…”

An EPG Study of the Probing Behavior of Adult <I>Bemisia tabaci</I> Biotype Q (Hemiptera: Aleyrodidae) Following Exposure to Cyantraniliprole

“…The new diamide insecticide cyantraniliprole (DuPont Cyazypyr), a ryanodine receptor agonist, both controls B. tabaci population and interferes with pest feeding behavior (Cordova et al 2006, Cameron et al 2013). Recent Þeld trials on different crops conÞrm the direct action of this insecticide on B. tabaci populations in Italy (Wiles et al 2012) and India (Mandal 2012).…”

“…Recent Þeld trials on different crops conÞrm the direct action of this insecticide on B. tabaci populations in Italy (Wiles et al 2012) and India (Mandal 2012). With the use of a ßuorescent technique, Cameron et al (2013) recently demonstrated that cyantraniliprole produced a signiÞcant reduction of B. tabaci nymphs feeding when compared with nymphs fed on plants treated with other insecticides such as imidacloprid or spirotetramat. In addition, cyantraniliprole is not affected by commonly occurring resistance mechanisms that are known to confer resistance to other insecticide chemistries.…”

“…: B. tabaci PROBING BEHAVIOR AFTER CYANTRANILIPROLE Although Þeld and laboratory tests may provide information about mortality caused by an insecticide application, other methods are needed to generate information on how the insecticide affects the feeding behavior of insect vectors (Cameron et al 2013). Among many methods, the electrical penetration graph (EPG) technique is the most rigorous way to evaluate the effects of an insecticide on the feeding behavior of vectors, and consequently, on their ability to reduce transmission or spread of plant viruses (Nisbet et al 1993;Costa et al 2011;He et al 2011;Butler et al 2012;Cui et al 2012;Jacobson and Kennedy 2013a,b).…”