Peach Tree Question

[MsPacMan]

I have a small peach tree orchard.


Today I went back there to cut the grass, and I found one plant with a peculiar problem I have never seen on peach trees before.


It looked from a distance like a branch of the tree was embedded in thick spider webs, but when you got closer, you could see that there were many worms embedded in the white thready mess, plus a butterfly or two. It was killing the branch it was on (I pruned that branch from the tree).


What is this problem?


And aside from pruning the branch off the tree (which is already done), what can I do about it?


I have a bunch of fruit treees back there, 30 feet from one another, so I really don't want this problem spreading across the orchard.

[skruzich]

Originally Posted by MsPacMan

I have a small peach tree orchard.


Today I went back there to cut the grass, and I found one plant with a peculiar problem I have never seen on peach trees before.


It looked from a distance like a branch of the tree was embedded in thick spider webs, but when you got closer, you could see that there were many worms embedded in the white thready mess, plus a butterfly or two. It was killing the branch it was on (I pruned that branch from the tree).


What is this problem?

Was the web on a branch or in the crotch of the tree?

If its in the branch its fall web worms. If its in the crotch of the tree branches, it is tent caterpillars.
Both will defoliate a tree and can kill them. You are going to end up having to spray them to get rid of them.




And aside from pruning the branch off the tree (which is already done), what can I do about it?


I have a bunch of fruit treees back there, 30 feet from one another, so I really don't want this problem spreading across the orchard.

Was the web on a branch or in the crotch of the tree?

If its in the branch its fall web worms. If its in the crotch of the tree branches, it is tent caterpillars.
Both will defoliate a tree and can kill them. You are going to end up having to spray them to get rid of them.

[skruzich]

Controls for fall web worms

Strategy 1: Mechanical Control - Removal of Nests - Small nests can be pruned out of small to medium trees. Monitor trees early to detect the nests when only several leaves are involved. These small nests can be easily crushed. Do not burn or torch the nests in trees as this may do additional damage to the tree.

Strategy 2: Biological Control - Encourage Predators and Parasites - Over 80 species of parasites and predators have been identified in North America. Social wasps (yellow jackets and paper nest wasps), birds, predatory stink bugs and parasitic flies and wasps are the most important. Delay destruction of wasp nests until August when social wasps change from carnivores to sugar feeders. Try to withhold contact insecticide sprays until it is certain that predators and parasites are not present in sufficient numbers to control the webworms.

Strategy 3: Biological Control - Apply Bacillus thuringiensis (Bt) - The bacterial insecticide, Bt, is quite effective against fall webworms if it is applied when the larvae are small. Use formulations with UV protectants and thoroughly cover leaves next to nests. As these leaves are incorporated into the nest and eaten, the Bt will be ingested.

Strategy 4: Chemical Control - Standard Insecticide Sprays - Most applicators attempt to "blow" the nest out of the tree with a strong jet of insecticide mix. While this generally works, more material is often used than is needed. Locate nests early and merely wet the nest and cover nearby foliage. As the larvae walk on the nest surface or incorporate new foliage, they will contact the insecticide. Second applications may be needed if additional generations occur. See Bulletin 504 for currently registered insecticides.

Strategy 5: Chemical Control - Use Systemic Insecticides - Extensive nests may occur in tall trees which are difficult to spray with ground equipment. These trees can often be treated with translocated systemics applied to the soil for root uptake or injected. See Bulletin 504 for currently registered insecticides.

[skruzich]

Controls for TEnt Caterpillars.

People often get overly concerned when they see large numbers of nests in roadside wild cherry. Fortunately these pests rarely reach large populations in ornamental trees.

Strategy 1: Mechanical Control - Destroy Egg Masses and Nests - The egg masses are easy to spot after the leaves have dropped in the fall. Simply clip off and crush or dispose. If egg masses were undetected, there is ample time to hand remove any nests in the spring. It is suggested that a glove be used as the caterpillar hairs are irritating to some people. Simply scrape the nest off onto the ground and crush the caterpillars or drop them into a pan of soapy water. Early morning or late afternoon is best because most of the caterpillars will be in the tent.

Strategy 2: Biological Control - Use Bacillus thuringiensis (Bt) - Most commercial Bt products for caterpillar control will work on the tent caterpillars. Make applications to the plant foliage while the larvae are small. Numerous predators and parasites also attack this pest but in some years these agents do not arrive in sufficient numbers to adequately control tent caterpillars.

Strategy 3: Chemical Control - Insecticide Sprays - Most contact and stomach insecticides rapidly control this pest. Direct sprays to the plant foliage and nest. The larvae are usually easy to contact if spraying is done in late morning when the larvae congregate on the tent surface to warm in the sun. See Bulletin 504 for currently registered insecticides.

[Oxankle]

We have infestations of tent caterpillars here in the pecan groves. We have found that simply spraying the trees and tents with a soap solution will destroy the worms. This was on the advice of our local pecan expert at the state extension service.

I use the cheapest dish detergent I can buy and put a bottle of it in each 50 gallons of spray. Last year I got each bottle of detergent for $1 at the dollar store, probably 28 or 32 oz bottles.

The soap does not poison the webworms, but it seems to destroy the web's ability to shelter them and they do no more damage. Unless washed off by rain the soap remaining on the trees deters the next generation as well. I apply this with a mist blower that will reach the tops of most of my trees.

I have never seen a tree killed by either the webworm or the walnut datana, a similar webbing insect. They simply defoliate them, in some cases to the point where they will not bear the following season.

If soap is not lethal enough for you, a malathion spray is fairly innocuous and very effective. BT works fine, but it has only a limited period of action.
Ox