Watch for possible plant injury from pesticides

Every year, pesticides damage plants. It’s a good idea to review some of the ways this can happen and what the symptoms are.

The most common problem is applying the wrong chemical or using the wrong rate of application. This can cause severe damage or kill the plant, so remember to always read and follow the directions on any pesticide.

Remember that more is not necessarily better.

Some plants are especially sensitive to certain products. Sensitive plant species are usually listed on the label, but if you’re unsure, it’s best to test the product on a few of the lower leaves before spraying the whole plant.

Another source of plant damage is spray drift. This happens when the wind blows the chemical away from the target to nearby plants.

Water runoff can also move pesticides off target. This may happen above ground with irrigation or rain as well as below ground as water moves through the soil.

The symptoms can give clues about the way the plant was contaminated as well as the product doing the damage.

Spray injury usually shows on just one section or one side of the plant. It often causes burned spots on the leaves but can cause whole areas to die back.

Herbicides taken up through the roots generally cause symptoms throughout the whole plant. Damage appears on new growth some time after contamination. On conifers it may appear in a spiral pattern up the tree.

Herbicides work in different ways; therefore they cause a wide range of symptoms, depending on the product used.

Some, like Casoron, may cause leaf tips and margins to turn yellow and later brown. Leaves may turn yellow only between the veins, or in some cases the veins themselves turn yellow or white.

Products like Roundup may kill some or all of the plant. New growth will be straplike and contorted, and the plant may take on a pinkish cast. The herbicide 2, 4-D may cause cupping or twisting of leaves, while Dicamba makes leaves curl.

If you suspect pesticide damage in your yard, you should consult a landscape professional, or bring samples to the Master Gardeners Plant Clinic, 222 N. Havana St.

Bring samples of healthy leaves as well. Take a picture of the plant.

If a plant becomes contaminated, the best option is to give it plenty of water to help dilute the chemical and wash it out of the root zone. You should remove any dead limbs from trees and shrubs. Often the plant will grow out of the damage if you give it time.

In the garden this week

Keep your plants healthy by giving them extra water.

Now is the time to start preparing trees for winter by giving them deep watering throughout the root zone.

Continue deadheading annuals to keep them blooming until frost. Do not fertilize plants anymore, as this may cause new growth when they need to be preparing for winter dormancy.

Enjoy the harvest of your own vegetables or admire other gardeners’ skills by visiting the local fairs in the next few weeks. Donate your excess produce to area food banks.

Speaking of harvest, you can prevent next year’s weed crop by keeping your yard weed-free now.

Take some notes about what worked in your garden and what could be improved next year. Don’t forget to find a spot or two for planting spring bulbs as well.

It’s never too early to plan for next year, but don’t forget to stop and enjoy the late-season garden while it’s still here.