Ants Not Good Guys in Fruit Production

Q. I searched your blog but could not discover if ants are good pollinators or not. I know bees are. I have over 2 acres in Sandy Valley and have seen 6 to 8 different types of ants scurrying about the property. Are ants beneficial or will they become a problem for fruit trees I am planting? 

Ants and aphids living and working together on apricot. The aphids suck plant juices and release sugary excrement. The ants use this sugary excrement as a food source and take it back to their nest in the ground. Ants move aphids to new locations in the tree or neighboring trees that are touching to expand their "herd" of aphids.

A. The best pollinators for fruit trees, hands-down, are honeybees. More specifically Italian honeybees, the type that produce honey collected by beekeepers. They are workhorses when it comes to pollinating fruit trees and vegetable gardens.

Female leaf cutter bees cut nearly perfect circles in the leaves of many plants including grapes and fruit trees. These leaf circles are used by the bees for raising their young.Leaf cutter bees are good pollinators of late season flowering plants.

            Other types of bees, solitary bees like the leafcutter which cuts near perfect circles in the leaves of roses, grapes and basil, are strong workers later in the year and important pollinators for late spring and summer bloomers like alfalfa and clover.

Rosemary is a good winter and early spring flowering plant to encourage pollinators for spring pollination of fruit trees.

            Ants don’t contribute anything to pollination of fruit trees in my opinion. I consider them mostly nuisance insects that contribute to insect problems in fruit trees in a secondary way. How? They love aphids and will defend them to their death against anything or anyone that threatens aphid populations.

 

This short video is taken at our family farm in the Philippines. It shows Weaver ants, that create their nests in the canopies of trees, protecting some scale insects they have moved and are now farming on the branches of tropical fruit trees. Ants do the same thing in temperate environments but most of our ants have nests in the ground.

            In fact, ants distribute aphids throughout a fruit tree canopy similar to how we move cattle to new pastures. Aphids are common in the spring of the year feeding on new growth of fruit trees. Their feeding causes leaves to become sticky, roll and curl. Ants move mother aphids around to increase populations and their own food supply for subterranean nests.

            While feeding on plant leaf juices, aphids drip sugary excrement that ants use for food inside their colony. Next time you find an aphid problem in fruit trees, look at the ground nearby. You will see an “ant mound”, an opening to a subterranean ant nest. There is a good reason for their close association to aphids.

            For this reason, I don’t like ants in orchards and I make a point of eliminating ant colonies when I see them near fruit trees. Several methods can be used to eliminate them but I find ant baits, taken back inside colony, to be among the most effective. Seldom are ants beneficial when growing plants for human food.

Shiny Leaf Sheen on Roses May Be Aphids Feeding

Q. There's a glossy sheen on my rose leaves that's not suppose to be there. I have the problem every year and I usually just give them a good spray with the hose and that helps but doesn't seem to be the cure. Any suggestions that don't involve chemicals?

Dark Brown or Black Shells on Oleander May Be Scale Insects

Q. I have a serious infestation of hard shelled black insects on my oleanders. I have a tree-like hedge of oleanders on both sides of my home. One of the oleanders is heavily infested but the problem is spreading rapidly to all the others.

Ants Farming Aphids on Pyracantha

Q. We have a couple pyracantha bushes. We noticed this past summer some small, pen point sized, bright green bugs on the end of the branches. A day or two later I noticed ants in those same places but couldn't tell if they were eating the bugs or not. Please advise if we need to do something.

 

Pyracantha, sometimes called firethorn,, with its red berries.Some have orange, yellow and off-red.

A. From the sound of it the bush had aphids, sometimes called plant lice, but summer is not the usual time that aphids appear. Aphids normally appear with new growth in the spring and disappear when it gets hot.

            Ants are attracted to aphids because the aphids release sugary honeydew when they're feeding on the pyracantha leaves.

Leaf cupping on plums due to aphid feeding in the spring.

            Ants “farm” the aphids, take this honeydew excretion and use it. So you may see ants traveling up and down the pyracantha gathering and transporting honeydew to their nest in the soil. Ants may even move the aphids around to new locations to expand their “herd”.

            It's not a big problem if these are just aphids. The aphids will cause some stickiness on the leaves and may cause leaves to fall from the plant if the feeding becomes heavy. But that time of year I would not expect them to be a big problem.

Ants herding aphids for their honeydew

            If the problems is excessive the easiest thing to do is mix some soap and water, about as much as you would use when you would wash your dishes. Put it in a spray bottle and spray the soapy mixture directly on these green bugs, usually on the underside of the leaves.

            You will probably have to do this every couple of days since soap and water does not leave any poisonous residue on the leaf surface and these spots will repopulate quickly after the spraying is done.

            If you want more permanent control then you can use a traditional insecticide that has a label listing ornamental plants and aphid control. You can also treat the ant nest in the soil. Pouring boiling water on the ant hill will give some temporary organic control of the ants.