It’s Summertime in the Garden, and Plants Are… Sticky?

During the growing season, cases of stickiness occur in the garden and landscape. Sticky fingers hold melting Popsicles, and sticky faces press into watermelon slices. Sometimes plants get sticky too. In all cases, a quick spray with the garden hose does the trick.

But why do plants get sticky? One cause is aphids.

There are many species of aphids, so the small, soft-bodied insects come in many sizes, shapes and colors. Some are green; others are pink, red, yellow, dark blue, brown, gray or black. Some have wings, others do not.

The pests attack many different plants, including vegetables, legumes, stone fruit crops, apples and ornamentals. Their colonies hang out on the undersides of leaves, and they love fresh new growth and the tips of new shoots. Young leaf and flower buds are their favorite targets.

Aphids attack their targets with a probe-like device called a stylet. Through their stylets, aphids suck plant sap. Aphid sap-sucking robs plants of the products of photosynthesis. The result is curled or twisted leaves and yellowed foliage.

Another result is plant stickiness. When aphids pierce a plant to suck its sap, the high-pressure liquid goes straight through them. The liquid is excreted as sticky honeydew.

Ants are attracted to honeydew and will protect its source. To ensure aphids are defenseless against their natural enemies, control their ant protectors with sticky barriers around trunks or branches. This aphid-fighting strategy is an example of integrated pest management, or IPM.

With IPM, pest control actions start with the least toxic. An IPM approach to aphids includes: selecting plants aphids find unattractive, knocking aphids off plants with a forceful stream of water and pruning and destroying infested plant parts. To avoid spreading aphids or other garden problems, clean and sanitize pruners after each cut.

If you are not squeamish, rub leaves or stems between your fingers, squishing aphids as they feast.

Another tactic is reducing the use of fertilizers so the nitrogen-fueled green growth aphids savor is not produced.

Be patient with low-to-moderate aphid populations, holding off on using pesticides, so birds, lady beetle adults and larvae, lacewings and parasitic wasps can eat your pest problem for you. Most of the time, a strong stream of water and help from these natural aphid enemies make pesticides unnecessary.

Some gardeners try augmentation, or the release of a pest’s natural enemies, to control aphids. More research is needed to tell if this IPM strategy is effective in home gardens.

If you choose to use a pesticide, know that most kill beneficial insects too. This may make your pest problem worse. Select products least toxic to beneficial insects, such as soaps, oils, microbials and botanicals. Spray only where the infestation is and when beneficial insects are not present. Always read and follow label directions.

No matter your aphid control strategy, know a little stickiness in the garden is not a terrible thing. It can be a fond summertime memory in the making, such as enjoying a Popsicle or watermelon slice while watching lady beetles do their work.

Ashley Andrews is the horticulture communications assistant with University of Nevada Cooperative Extension. Horticulture questions? Contact a Master Gardener at mastergardeners@unce.unr.edu or visit www.growyourownnevada.com. Our next class, Managing Stormwater Runoff, will be held June 14 at 6 p.m. at 1325 Waterloo Lane in Gardnerville.

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