Pests Seen Early Around The Nursery
Insects, pests, bugs, arthropods, mites, critters, *#@*%^#!!!! - No matter what you call them, they can evoke strong emotions. So, I decided to review some of the damaging insect-type pests that emerge early in the year.
One of the first insect pests that usually rears its ugly head is the Aphid. Also called plant lice or greenflies, these little ladies can easily be identified by the twin cornicles, or “tailpipes” and the tail-like cauda found on their back ends. Aphids come in a variety of colors and combinations, including green, yellow, black, red and orange. These little sapsuckers are akin to Tribbles of the Star Trek universe in that they are “practically born pregnant.” No, seriously. Aphids reproduce asexually for most of the year, bearing live young without the need for male “assistance.” There is even evidence that the mother has a daughter within her that also has a daughter already developing.
Aphids have developed some, very nifty survival tricks. When a colonized plant becomes overcrowded or unthrifty, the “girls” start bearing winged offspring that fly to other plants and begin new colonies. As autumn progresses, these ingenious little ladies begin producing both males and females. Sexual reproduction is needed to produce the eggs that will survive through the winter, hatching into a new generation of females who begin the cycle all over again.
When Do You See Aphids?
Now, that’s all very interesting but when do you start seeing them on your plants? In my experience, as soon as there is anything budding, flushing or turning green – you could begin seeing aphids. They show up as early as January inside our polyhouses. When scouting for the insects, also look for the deformed leaves or shiny honeydew that result from their feeding activities. Several predators find aphids quite tasty, so look for the pest anytime you see an upswing in the Ladybug, Green Lacewing or Hoverfly populations. Some ant species even farm aphid colonies for the honeydew, so be sure to look for aphids if you begin seeing lots of ants.
Getting Rid of Aphids
Next question – how do you get rid of them? In spite of (or perhaps because of) their prolific nature, these soft-bodied insects are pretty easy to kill. Keeping them under control is much harder. Natural enemies that help keep aphid populations in check abound. Aphids can be knocked off plants with a strong stream of water, which is a good homeowner or garden center technique. Horticultural oils and soaps are soft chemical options which can provide good control yet preserve the beneficial population. Stronger chemical options include pyrethroids (e.g., Astro, Talstar), organophosphates (e.g., Malathion) and neonicotinoids (e.g., Tristar, Marathon), all of which must be used with care (READ the LABEL). Strangely, Sevin is not the best aphid option. Control is marginal and it kills many beneficial insects that could help with the aphid problem. No matter what options you choose for control, complete coverage and alert vigilance are the keys to success.
Other creatures that show up early in the year are the Eriophyid mites. Also called rust, bud, blister and gall mites, these are not like normal spider mites, oh no. “E. Mites” are so tiny that they can only be seen under magnification. The first ones I ever saw made me think of carrots with legs waving from the larger end. With only two pair of legs and elongated, spindle-shaped bodies, they don’t resemble traditional mites.
How can you tell that you have them? Often, the first evidence that you have a problem will be the abnormal plant growth caused by the E. mites’ feeding. Deformed buds, rough looking new growth, strange looking galls, witches brooms, bronzing or russetting of leaves or fruit – these are all plant responses to look for. But why does the plant react so extremely to these mites? As they feed, E. mites inject a toxin into the cells that causes something akin to an allergic reaction within the plant.
E. Mite Species
Although E. mites are very plant specific, there are a lot of different species found worldwide. We have found them comfortably ensconced with the terminal buds of Junipers, frolicking on Hemlock needles and Golden Privet leaves and reveling inside a wildly growing Echinacea. These pernicious little creatures are difficult to manage, but it can be done. Remove all plant debris when pruning, that helps reduce the numbers you have to contend with. Start scouting for the mites when the red maples begin blooming. Horticultural oil applications can help control them, as well as some miticides such as Avid, Judo, Akari and Sanmite. However, as I’ve mentioned before you have to read the label to make sure that you are using the correct product. Eriophyid mites are not like spider mites and not all miticides will affect them.
Another insect you may glimpse early in the year are the Tent Caterpillars. The first sign we usually see is a thin skin of fecal-spotted webbing in the crotch of a tree. If you look closer, the caterpillars can be seen inside the webbing as well as on the surface. Their webbing acts as a heat reflector, raising their body temperatures and enabling them to feed effectively. Early detection is important as tent caterpillars forage outside the tent area when it becomes warm enough. The warmer the weather, the farther the caterpillars forage, defoliating more and more of the tree.
If you catch them early, tent caterpillars are pretty easy to control with pyrethroids, as long as you have good coverage. The webbing can make that very difficult. Since we handle relatively small quantities of trees, we use a wasp and hornet spray. Tent caterpillars are on the label and the strong spray forces the insecticide into the webbing, ensuring contact. Targeting nascent colonies in this manner reduces the overall amount of insecticide in the environment, protecting both beneficial insects and customers. Because face it, you need those beneficials to help control the aphids!