If only we could garden without the insects, what a great place Texas could be.
But they’re here, and so are we, and we must learn to identify and deal with the issues they bring us. Here are some of the most common for this time of the year. Look, and you may find.
? Bagworms. Not to be confused with tent caterpillars, these larval insects feed almost exclusively on cone-bearing plants such as junipers, cypresses, arborvitae and cedars. They begin their active feeding stage as tiny caterpillars no larger than the sharpened end of a pencil, always carrying a fibrous bag constructed from the needles of the host tree behind them.
As the larvae grow larger, so do their bags. Finally, several weeks into their feeding and when the caterpillars have grown and completed their bags at less than 2 inches in length, they seal themselves within the bags and tie the bags to twigs of the host plants with tough fibers that hold them in place for months, actually years. The following spring, the moths will emerge, eggs will be laid, and the process will begin over again.
Control bagworms by watching closely for their early feeding. They are already active at this time. When you first see them, spray with Bacillus thuringiensis, Spinosad, or other labeled product. If you wait too long your only recourse will be to pick them off by hand, not a pleasant task.
? Webworms. What you will see in late spring will actually be eastern tent caterpillars. Webworms create shrouding webs that hang over the ends of branches of pecans, walnuts and several other species of trees. Tent caterpillars, by comparison, are generally within the crotches of the branches. In either case, try to break open the webs to expose the caterpillars to plundering birds. Use Bt or Spinosad sprays to kill them.
? Slugs, snails and pillbugs. These are pests of the cool, wet times of spring and early summer. They hang out in moist, mulched beds and they come out to feed primarily at night. Control them with Sevin dust or one of the several baits.
? Fire ants. They aren’t so much pests of your garden plants, but the small red or dark brown pests like to hang out in freshly tilled garden soils. They’re very aggressive, and when you disturb one of their colonies they will swarm instantly to let you know their displeasure.
Fire ants also build large mounds following rains to move their queens up out of the waterlogged soils. The best control practices involve area-wide baits that offer six-month protection for entire landscapes and perimeters of house foundations. Accompany that with individual mound treatments where they have built mounds near entries, in play areas, or adjacent to homes where they threaten to move inside with you.
? Lace bugs. If you’re seeing small, mottled tan spots on the upper surfaces of leaves of azaleas, Boston ivy, gray cotoneaster, sycamore, lacebark elm, bur oak or pyracantha, that’s almost assuredly damage of lace bugs. The surefire way to tell is to turn the leaves over. If you see small black, waxy specks, they would be the excrement. You may even be able to see a few of the adult pests with clear wings on the backs of the leaves.
Lace bugs can be stopped quickly with application of most general-purpose organic or inorganic insecticides. Be sure the spray coats both top and bottom leaf surfaces.
? Crape myrtle bark scale. We’ve discussed these before here. They look like cigarette ashes plastered up and down the trunks. They exude a sticky honeydew residue that drops onto leaf and stem tissues as well as hard surfaces below. Black sooty mold grows in the honeydew. To stop all of it before it ever starts, use a soil drench of Imidacloprid around the drip line of each crape myrtle plant. In university research, that approach has proven to give the best season-long prevention and control of the pest.
? Aphids. These small, pear-shaped pests are found in large numbers on tender new growth of many types of plants. You’ll see them in reds, yellows, greens, creamy whites, brown and black, always with what looks like twin exhaust pipes on either side. They can often be blasted off the plants with a hard stream of water, but they are easily controlled with almost any general-purpose organic or inorganic insecticide.
? Spider mites. The most universal “insect” pest of landscape and garden plants in Texas, these are actually mites. That means they have eight legs and are more closely related to ticks and spiders than they are to true insects. They suck plant fluids from the leaves of your garden plants causing them to become mottled light tan, then almost white, then browned and crisp. They kill more garden plants than any other pest that we have, yet they’re the smallest of all our common invaders.
If you think you have a marigold, tomato, juniper or other plant with spider mites, thump a suspect twig or leaf over a sheet of plain white paper. If you see nearly microscopic specks start to move about freely after a few seconds, those would be the mites. Look at them under low magnification and you’ll see their eight legs.
We no longer have access to specific miticides at the consumer level. You’ll have to look for a general-purpose insecticide that says it can give control of mites or spider mites. Apply it so that you coat both top and bottom leaf surfaces. Wait 10 days, then try the “thump” test on another leaf or twig. If you still see mites, spray again.
? Leaf rollers. There are several species of insects whose larvae use their host plants’ leaves to form cocoons. They roll themselves up within the leaves and wait for the metamorphosis as the change into the adult flying insect. Control them with early application of a systemic insecticide prior to the formation of the molds.