If the rumors are true, there are still insect and mite problems on greenhouse crops. The problems are being caused by the usual suspects–the pest group names have not changed much over the decades (although individual species within groups have varied). There’s just been a periodic reshuffling of the rankings in a kind of whack-a-mole scenario.
The current top pest group listing includes aphids, mealybugs, thrips, fungus gnats, whiteflies and spider mites. Also fighting for top rankings are leafminers, caterpillars, shore flies and other mites (i.e. broad mites). As with any ranking of best or worst, you might have another list of top pests depending on what crops are being grown.
The reasons why there are a fairly constant group of insects and mites to deal with are already well known (rapid pest reproduction cycle, wide host plant range, growing crops in protected environments, continuous production, etc.). These reasons are not going to change much as long as greenhouse plant production continues. So, we have to deal with the existing system and see if we can continue to make it work.
The good news is there have been a few recent registrations of insect and mite control products and formulations for greenhouse and/or nursery use–nothing really radically different from what is already out there but useful to add to your rotation programs to help control several of the major pest groups. The following section will summarize some of these newer products, in alphabetical order by trade name, and where they might best fit in a program for controlling some of the most serious insect and mite pests.
Beethoven TR (BASF)
Beethoven, possibly a better name than Willie Nelson, is a well-known composer and also a Total Release aerosol product containing etoxazole, the same active ingredient as in TetraSan. It is an aerosol formulation that’s registered for control of spider mites (and whitefly suppression) on greenhouse ornamentals.
The active ingredient etoxazole is classified as a mite growth regulator and is most effective on eggs and youngest immature stages. Activity is by contact and ingestion. As a growth regulator, activity is slow, so Beethoven should not be used to reduce a well-established spider mite (or whitefly) infestation. Products with rapid activity on nymphs and adults should be added to the rotation.
Hachi-Hachi is the name of several Japanese restaurants, a Japanese card game and now an insecticide. Do not confuse them. Hachi-Hachi is an emulsifiable concentrate (EC) formulation that is registered for control of aphids, leafhoppers, caterpillars, scales, thrips and whiteflies. It is registered only on greenhouse ornamentals with outdoor uses pending. Activity is mainly by contact.
Tolfenpyrad is a new active ingredient registration on ornamentals but not a new mode of action. Insecticide Resistance Action Committee (IRAC) mode of action group 21A is getting pretty crowded and now includes products such as Sanmite, Akari and Magus, in addition to Hachi-Hachi. These are all called METI acaricides and insecticides. Most have activity against some insects and all but Hachi-Hachi have one or more mite species listed on their labels.
The general rule of resistance management is to avoid rotation among products with the same mode of action, unless two or three applications of products in different mode of action groups are applied before doing so. The label states to apply no more than two applications per crop cycle.
The best fit for Hachi-Hachi seems to be in a rotation for western flower thrips control, which has ranged from fair to very good in trials. It is also worth looking at for control of the other labeled insects. Activity is said to be quite slow, so tank mixing or alternation with faster-acting products might be needed.
Magus (Gowan Company)
A Magus is defined as a member of a hereditary priestly class among the ancient Medes and Persians–as well as the brand name for a new mite control product. Magus is a new active ingredient for ornamentals, but also is a member of IRAC’s Club 21A which includes several other mite and insect control products.
Magus is sold as a 200 SC (suspension concentrate). It is registered for control of spider mites, tarsonemid mites (broad and cyclamen mites) and eriophyid mites (rust mites and other species). There are no insects listed on the label. Magus is active by contact and ingestion, has fast knockdown of adults and is said to control all mite stages.
Label directions state to apply before mite infestations build, which is excellent advice for just about any pesticide application for controlling any insect or mite. Resistance management directions state to make only one application per crop cycle. If Magus is used in a mite control program, avoid using other products from IRAC group 21A until at least two applications of products with alternate modes of action have been applied.
A Sirocco is a Mediterranean wind from the Sahara that can reach hurricane strength–and also a new combination miticide-insecticide containing the active ingredients in Avid and Floramite. It is available as an SC formulation. Sirocco is primarily a broad-spectrum mite control product but also will help control or suppress several insects. Activity is by contact and ingestion. The combination of the two active ingredients provides rapid knockdown and good residual control.
As expected from such a combination, Sirocco is registered for control of numerous mites, including spider mites, red mites (citrus and southern red mites) tarsonemid mites (broad and cyclamen mites) and eriophyid mites (bud mites).
Insects on the label include leafminers, aphids, thrips and whiteflies. Activity on aphids, thrips and whiteflies is listed as suppression. As well as numerous mites, Sirocco should help manage the labeled insects, especially leafminers and thrips.
So, yes, there still are new insect and mite control products being registered. Most growers will continue to use pesticides as key components of insect and mite management programs on greenhouse crops. Resistance selection begins with the first application.
It’s going to happen. Help delay resistance development. Use a pest management program that integrates other control methods. Most products are pretty effective, but anything done to help them out will make them even better and remain effective longer.