Be responsible with herbicide use

To respect neighbors, inform them and watch for drift

Last week, I saw a lot of stretched-out or ropy damage on vegetable plants and heard that our area grape growers are seeing this as well.

At the same time, I’ve been getting a lot of calls about weeds.

These two problems are related. The drought the past year left a lot of open spots for disturbance species, otherwise known as weeds, to invade lawns, gardens, pastures and any other location a plant is in a spot where it is not desired. People are spraying more, which means there have been more reports of herbicide drift damage.

When checking for herbicide damage, this is what I look for.

One, I look at the foliage. Herbicide damaged plant foliage will stretch out, like the leaf was taffy or silly putty and you were attempting to pull it. Another sign is leaf cupping with the outside edge rolled up. Ropy, string-like foliage can indicate herbicide damage, too.

These symptoms can sometimes match those of vegetable viruses, particularly cucumber mosaic virus. One can tell the difference by getting the plant tested. This is expensive, and there is an easier way to tell.

Viral damage will be a couple of plants, here and there, unless the seed was contaminated with the virus or there was a large outbreak of the insect vector that transmits the virus. For example, if all 20 tomato plants are showing ropy foliage, that is unlikely to be cucumber mosaic virus.

Also, viruses typically do not jump from plant species to plant species, either. For example, a tomato plant is incredibly unlikely to give its viral infection to a bean plant (though this doesn't mean it can't happen). If multiple types of vegetable are affected in a garden, it's likely herbicide damage.

I have nothing against spraying weeds in lawns or pastures, but I urge you to be responsible when you do it. Get to know your neighbors and the surrounding areas, not just those adjacent to you.

Some of these herbicides can drift more than a mile. If someone nearby grows vegetables, fruits or grapes, do not spray when the wind is blowing in their direction. Avoid spraying when the air is perfectly calm, as well. This calmness could be the result of a temperature inversion, and it can cause pesticide drift, too. The ideal windspeed for spraying pesticides is 3-7 miles per hour.

When you apply your pesticides, whether around the house or pasture, use a larger droplet size. A fine mist is more likely to drift.

Herbicides are most effective on annual plants, like musk thistle, before they flower. If you spray them now, when they are big and obvious, they will die but they will also set seed. If you have open areas, you have just seeded the area with that weed for next year. Cover the ground, either with a desirable plant or cover crop, to prevent weeds.

Additionally, mowing higher in the summer and decreasing livestock stocking rates during drought, will help more plants survive, which means there are less bare spots for weeds to grow.

Herbicide damage is not just limited to airborne drift. Some types of herbicides, including a lot of the ones used to treat hay, don't go away in dead plants. These herbicides can continue to persist even if eaten and excreted by an animal.

The bagged animal manure is usually safe, but if you use locally harvested manure or hay in your vegetable garden or flower beds, be forewarned it might be contaminated. If you’ve had this problem, it's going to take a couple of years for the herbicide to break down. Growing an annual grassy cover crop grass in that spot can help break it down faster.

If your plants got hit with what you think is pesticide drift, verify it as best as you can, and if you want to make a formal report, contact the pesticide department at the Texas Department of Agriculture 512-463-7622. My office can help you identify pesticide damage, but we are educational, not enforcement.

Herbicide damage cannot be fixed. The plant either has to be removed if it is severe or given a chance to grow past the damage if light.

I can't say if the risk of herbicide damage will continue. It depends on how much rain we have, because while rain grows good plants, it also grows weeds, too.

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