Plant maintenance will lead to fewer pests

I always forget about the upcoming insect pests and other plant problems as I eagerly wait for spring to come each year. Then, as the lilacs and other flowers start blooming, as roses start to grow and ash trees develop their leaves, I’m quickly reminded.

Some of the first pests of spring are aphids. They are congregating on the new growth of roses. They have already curled the developing leaves of ash, plum and other trees. Aphids come in many colors — white, orange, green, black or tan. They suck the juices out of plants and then leave their sticky residue all over, which drips on anything underneath it.

Pines, sequoias and other evergreens are showing signs of stress as the temperatures rise. Most of these trees have an amazing ability to look good long after they have suffered last summer’s drought or insect attacks and then winter’s drought stress. However, the warmer weather dries them out and they can no longer hide signs of decline. Pine needles have brown tips, one sign of insufficient water through the last few seasons, particularly winter. Some pines are infested with scale, a sucking insect that’s a relative to aphids. Sequoias turned brown during the winter. Some are coming back, but too many are not. Colorado blue spruce needles are showing a pink tinge or turning brown and spider mites seem to be starting on dwarf Alberta spruce.

I am seeing stink bugs on my lilacs. Adult stink bugs are shaped like shields. They are usually only sporadic pests, but we may see damage on fruit as summer progresses.

What’s a gardener to do? Hose the aphids off the roses, squish them or try insecticidal soaps or horticultural oils. You can blast the aphids off the ash trees with a power washer attached to the hose or spray them with soaps or oils. While there are systemic insecticides available for aphid control that you put around the base of the trees, there is controversy about the effect of these chemicals on bees. One constant and important maintenance chore is to water trees deeply out to the drip line to a depth of at least 15 inches. Hose off dwarf and other spruces to keep spider mites down. We can live with stink bugs if infestations are minor.

Healthy plants usually resist pests. Provide the right amount of water, nutrients and proper maintenance and your plant pest problems will be few.

JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at or 887-2252.


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