Finding solutions to ant, aphid problems for gardners under siege

By Rennie Phillips

There are lots of common garden pests that literally will almost bring a gardener who is a preacher to swear. Almost! Some years I have more trouble than normal, and this is one of those years.

Almost from the beginning I have had trouble with aphids and ants in my greenhouse and high tunnel. Thousands of ants. I had ants even cause some of my plants to get sick and almost die. And if it wasn't the ants, it was the aphids.

Aphids are a really small, almost transparent, pear-shaped little critter. Most are about the size of the head of a straight pin. Most of those on my tomato plants appeared to be just a white speck on the leaves. Some of the larger ones, and I'm assuming older ones, are darker and almost a tan color. One place I read said these tan-colored ones were older and dying. Some were on the bottom of the leaves and some on the top.

When you first see them they almost appear like they aren't moving. If you touch the white speck with something, you will notice it is moving. Not a lot of movement, but it is moving. They move really slow.

A great aid and gift for a gardener is a magnifying glass. Mine has a small light in it, which really helps. Not sure how fast they reproduce, but it seems like there are a few today and bunches tomorrow. One source I was reading said adult aphids can reproduce up to a dozen new aphids daily, while another said up to almost 100 on a weekly basis. Most of what I read said the warmer the climate, the easier it is for aphids to reproduce.

A couple sites said ants and aphids are kind of dependent on each other, especially in cooler climates. Ants are almost entirely dependent on sugar of one kind or another. Aphids are sap suckers, so they suck the sugary content from plants, like a tomato plant. After the sweets have traveled their course through the aphid, the sugary excrements attract ants, who find it a delicacy.

The ants form an alliance with the aphids, even protecting them. Amazing how smart ants are. One place I read said the ants kind of store the aphids through cold weather and then turn them loose when the weather gets warmer. So if you have ants, you will most likely have aphids.

One mistake I've been making is I plant a cover crop in my tunnels, then leave it there all winter. One place I was reading said aphids will winter on these host plants. This is probably true, especially in my high tunnels and greenhouse, where they stay warmer all winter. I don't think I have ever had aphids on my outside tomato plants or other plants. Plastic mulches seem to help alleviate the presence of aphids, presenting a barrier under the plants. These mulches also cut down on the weeds, grass and such under the plants.

If you end up with aphids, the best time to take care of them is right away. They are relatively easy to control.

Some take care of their aphid problems by simply spraying their plants with a blast of water, which knocks off the aphids. This works pretty good.

I have used insecticidal soap and an oil spray I bought from a garden supply store. One person I talked to said they used just plain Ivory soap. The oil and the soap when sprayed on aphids simply smothers them. Since the aphids will be on both the bottom and top of the leaves, one will have to spray the entire plant from top to bottom. You can make your own insecticidal soap, but since it doesn't cost very much I'd buy some concentrate.

Some use neem oil, which is an extract from a tree. I've tried neem oil but had a hard time getting it to dissolve in the water in my tank sprayers. I did some checking and found several things will help it dissolve. Use warm water. I used cold, and it just doesn't work. However, don't use water so hot that it damages your plants. One place I read said to add some insecticidal soap to aid in dissolving the neem oil in the water. From what I've read, the spray could take a week or so to be effective.

If the oil spray or insecticidal soap or neem oil doesn't work, you can resort to tougher sprays, like malathion and others. The real downside to using chemicals is they kill both beneficial and troublesome pests. Some, like malathion, are devastating to pollinators like honey bees. So if you have to use one of these chemicals, do so late in the evening when pollinators shouldn't be present. I'd use them as a last resort.

One word of caution is in order. Check out any spray on just a plant or two, or if you have numerous plants you can spray it on a few. Make sure it's not going to burn your plant or hurt it. Also, don't spray during the heat of the day when the sun is shining. I would think the oil spray might concentrate the rays and damage your plant.

A great habit for a gardener is to walk your garden on a regular basis. Look for insect damage or stress.

Happy gardening.