April 2011

New or Unfamiliar Pest Control Materials By Raymond A. Cloyd

The availability of new pest control materials (in this case, insecticides and miticides) each year, particularly those with different modes of action, helps to deal with the array of insect and mite pests feeding on horticultural/floricultural crops. However, due to a number of factors including stringent federal and state regulations and the manufacturers’ costs associated with developing a new active ingredient, there have been fewer new active ingredients introduced than in previous years; although, there are new formulations of already existing active ingredients. As such, this article will discuss some “new” or “unfamiliar” pest control material active ingredients and those that individuals may not be fully aware of that we have trialed. These include acequinocyl (Shuttle), pyridalyl (Overture), azadirachtin (Molt-X), petroleum oil (SuffOil-X), spirotetramat (Kontos), fenazaquin (Magus), tolfenpyrad (Hachi-Hachi), sucrose octanoate esters (SucraShield) and sorbitol octanoate (SorbiShield90).

SucraShield

SucraShield (Natural Forces) is a sugar-based compound with the active ingredient sucrose octanoate esters (40 percent). SucraShield has contact activity only so thorough coverage of all plant parts is important. The product is labeled for control of aphids, mealybugs, spider mites, soft scales, thrips and whiteflies. The pH of the spray solution should be above 7.0. The mode of action of SucraShield is as a desiccant in which holes are created in the insect or mite cuticle (skin), which results in excessive moisture loss. The restricted entry interval (REI) is 48 hours and the product is registered for use in organic production systems. In our trials, the product was not effective (based on percent mortality) in controlling or suppressing populations of the western flower thrips.

Overture

Overture (Valent Professional Products), contains pyridalyl (35 percent) as the active ingredient. This insecticide is labeled for control of both thrips (including Western flower thrips) and caterpillars, and is formulated as a 35WP (wettable powder) available in water-soluble packets. Pyridalyl has both contact and stomach poison activity although the contact action may reduce western flower thrips populations faster than ingestion. This insecticide has translaminar activity on a number of plant types including chrysanthemum, transvaal daisy, hibiscus and poinsettia. Overture has a 12-hour REI, and the label rate for thrips is 8 ounces per 100 gallons. Furthermore, the product label specifically states that there should no more than three applications per cropping cycle or no more than three applications within six months. Based on our trials, pyridalyl does kill Western flower thrips nymphs and adults with mortality between 80 and 90 percent. It appears, however, that pyridalyl is more toxic to second instar nymphs (2.8 fold) than adults. One major difference between Overture and spinosad (Conserve), which is the insecticide primarily used to control or suppress Western flower thrips populations, is the speed of kill. In general, Conserve will kill Western flower thrips one to three days following an application, whereas Overture may take longer to kill a majority of Western flower thrips. As such, do not expect an immediate reduction in the Western flower thrips populations when using this insecticide. Research is being conducted to determine the direct and indirect effects of Overture on biological control agents (e.g., parasitoids and predators).

Molt-X

Molt-X (BioWorks) contains the active ingredient azadirachtin (3 percent), which is the same active ingredient (and concentration) in both Azatin XL and Ornazin. Azadirachtin is an insect growth regulator, which acts as an ecdysone antagonist by inhibiting the effects of the molting hormone ecdysone. As such, insect pests never reach adulthood. Azadirachtin is very sensitive to degradation when the spray solution pH is great than 7, which is why the recommended pH range is between 5.5 and 6.5. Application rates are 8 to 10 ounces per 100 gallons of water. Molt-X is registered for control or suppression of insect pests including whiteflies, leafminers, soft scales, mealybugs, thrips, aphids, fungus gnats, shore flies and caterpillars. In most cases, multiple applications will be required to suppress insect pest populations, and avoid outbreaks from occurring. Molt-X is also registered for use on many herbs and spices. The REI is four hours.

Kontos

Kontos (OHP Inc.) is an insecticide/miticide for use in greenhouses, nurseries and interiorscapes. The active ingredient is spirotetramat (22.4 percent) and the mode of action is a lipid biosynthesis inhibitor. The product is labeled for control or suppression of spider mites, aphids, leafhoppers, mealybugs and whiteflies. Kontos is formulated as a soluble concentrate and is labeled for use on vegetable transplants. The REI is 24 hours. This product has fully systemic miticide activity and according to the label, the active ingredient moves through the xylem (water-conducting) and phloem (food-conducting) tissues with the active ingredient residing in new shoots and leaves. It is primarily active via ingestion and may reduce female reproduction of certain insect and mite pests.

Kontos may be applied as a foliar spray or drench to the growing medium. In our trials, the product provided between 81 and 98 percent mortality of two-spotted spider mite populations seven and 14 days after application when applied as a drench to the growing medium. Based on our results, the active ingredient was more active on nymphs than adults. This may be due to the different feeding behavior of nymphs and adults. Young adult females, for example, tend to spend more time moving than feeding whereas nymphs or larvae remain stationary, thus affecting the amount of active ingredient ingested from plant tissues. It is important to avoid using Kontos on a number of horticultural/floricultural crops including geraniums, orchids and ferns. Also, consult the product label for a complete listing of additional crops that Kontos should not be used on. For control or suppression of two-spotted spider mite populations, it is important to apply the product preventatively (as a drench) or when populations are first detected because Kontos will not rapidly reduce “high” populations of the two-spotted spider mite or other pests. This is likely associated with the “low” water solubility of the active ingredient. Furthermore, for control or suppression of mealybugs, it is recommended to make two foliar applications at 14- and 21-day intervals so as to kill nymphs (crawlers) that emerge from eggs.

Magus

Magus (Gowan Company) is a new mitochondria electron transport inhibitor miticide with the active ingredient fenazaquin (18.79 percent). It is formulated as a suspension concentrate. It has contact activity, which means that thorough coverage of all plant parts is important for maximum efficacy. Magus provides quick knockdown of existing mite populations. This miticide is labeled for control of “mites” (and whiteflies). The label rate is 12 to 24 ounces per 100 gallons. It should not be applied to roses due to issues associated with phytotoxicity. The REI is 12 hours. This miticide has the same mode of action as Shuttle, Sanmite, Akari and Floramite.

SuffOil-X

SuffOil-X (BioWorks Inc.) contains petroleum oil (80 percent) as the active ingredient, which kills insect and mite pests by suffocation, blocking gas exchange and covering the breathing pores (spiracles). The product has activity on all life stages including eggs, larvae or nymphs, and adults of certain insect and mite pests. The application rate is 1 to 2 gallons per 100 gallons of water. SuffOil-X is labeled for use against aphids, fungus gnats, leafminers, mealybugs, mites, scales, thrips and whiteflies. Since oils only have contact activity, thorough coverage of all plant parts is critical, and multiple applications may be required to suppress insect and mite pest populations. The REI is four hours. In our trials, we found that one application of SuffOil-X, at 2 gallons/100 gallons, effectively suppressed populations of the sweet potato whitefly B-biotype (Bemisia tabaci) feeding on poinsettia after three weeks with no phytotoxicity.

Shuttle

Shuttle (OHP Inc.) is a miticide that contains the active ingredient acequinocyl (15.8 percent). The miticide is formulated as a soluble concentrate (SC), and is labeled for control or suppression of various spider mites including the two-spotted spider mite (Tetranychus urticae). Shuttle works by contact activity only, but is supposedly active on all spider mite life stages, including eggs. It kills spider mites quickly and one application may provide up to 28 days of residual activity. The label rate is 6.4 to 12.8 ounces per 100 gallons. Shuttle has a mode of action similar to fenpyroximate (Akari), pyridaben (Sanmite) and bifenazate (Floramite) as all four miticides are mitochondria electron transport inhibitors or METIs. However, whereas Akari, Sanmite and Floramite work in blocking electron transfer at Complex I in the mitochondria, the active ingredient in Shuttle binds to the Qo center of Complex III in the mitochondria reducing energy production by preventing synthesis of adenosine tri-phosphate (ATP). Regardless, it is important to avoid using any one of these four miticides in succession in a rotation program. In our trials, we found Shuttle to be more effective on two-spotted spider mite nymphs than adults. Also, since Shuttle does not have translaminar activity (meaning the material penetrates the leaf tissues and forms a reservoir of active ingredient even after spray residues have dissipated) more frequent applications may be warranted in order to suppress two-spotted spider mite populations. The REI is 12 hours.

Hachi-Hachi

Hachi-Hachi (SePRO Corp.) is yet another new mitochondria electron transport inhibitor miticide with the active ingredient tolfenpyrad (15.0 percent). Hachi-Hachi has contact activity only with no translaminar properties so thorough coverage of all plant parts is essential for control or suppression of certain insect and/or mite pest populations. The product is labeled for control of aphids, leafhoppers, caterpillars, scale, thrips and whitefly. Label rates are 21 to 32 ounces per 100 gallons; however, for cut flowers, the rate is 14 to 22 ounces per 100 gallons. The REI is 12 hours. Hachi-Hachi has the same mode of action as Shuttle, Sanmite, Akari, Floramite and Magus. This means there are now six mitochondria electron transport inhibiting miticides. In our trials, Hachi-Hachi was effective in controlling or suppressing populations of the green peach aphid (Myzus persicae).

SorbiShield90

SorbiShield90 (Natural Forces LLC) is another sugar-based compound; however, the active ingredient is sorbitol octanoate (90 percent). SorbiShield90 has contact activity only, which means that thorough coverage of all plant parts is essential. SorbiShield is labeled for control of aphids, mealybugs, spider mites, soft scales, thrips and whiteflies. Similar to SucraShield (described above), the pH of the spray solution should be above 7.0. SorbiShield90 has two modes of action; the first is as a desiccant in which holes are created in the cuticle (skin) resulting in moisture loss, and the second is as a suffocant — blocking gas exchange through the spiracles (breathing pores). The REI is 24 hours; however, this product is not currently registered for use in organic production systems. In our trials, SorbiShield90 provided minimal control or suppression (based on percent mortality) of western flower thrips populations, and was phytotoxic to transvaal daisy (Gerbera jamesonii) flowers. In conclusion, there are a number of “new” and possibly “unfamiliar” pest control materials that may effective (and some that may not) in controlling or suppressing insect and mite pest populations. As always, be sure to thoroughly read the label of all pest control materials to determine their characteristics and limitations.