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 Post subject: WEBWORM MIGRATION ?
PostPosted: Tue Aug 05, 2003 8:25 am 
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Location: San Antonio,Tx
I'd like to know how the webworms get into the pecan trees to begin with.

1] Do they just crawl over and up the trunk?

2] Larve left in the bark season after season?

3] Do they start off migrating up the tree or down?

4] Can an application of BT be applied prior to the worm season?

5] Can that season be identified?

I'm looking for prevention vs control after the fact.

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 Post subject:
PostPosted: Tue Aug 05, 2003 4:19 pm 
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Location: Dallas,TEXAS
i did some reading on webworm..and I have noticed a LOT of them this season in the larger pecan trees around here. Fortunately for me, my stinging wasps must be keeping them out of my trees...but, it seems that the webs are spun by the larvae after the adult moths have laid their eggs up on the tree tops. Here is the website I found most helpful..it is from Alabama, but I think that it applies to Texas as well:http://www.ag/auburn.edu/dept/entplp/fallwebsorm/fallwebworm.htmI


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 Post subject:
PostPosted: Tue Aug 05, 2003 4:43 pm 
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This is the link:
http://www.ag.auburn.edu/dept/entplp/bulletins/fallwebworm/fallwebworm.htm

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 Post subject:
PostPosted: Tue Aug 05, 2003 4:56 pm 
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Location: Dallas,TX
And a better one from Texas' "THE PECAN PRESS"

I bolded the last paragraph, as it definitely applies to my neighbors and not me... :lol:

http://pecankernel.tamu.edu/newsletters/news51999.html
-------------------------
This months column on fall webworm (Hyphantria cunea) is directed more toward the urban sector rather than the commercial producer. Throughout Texas, there are numerous communities with high populations of native and improve pecans around homes, parks and court houses.

During the spring, summer and fall many of these communities can literally become over run or engulfed by fall webworms. I’m not sure of the reason for this, but on more than one occasion I’ve heard the theory that this is from the adults being attracted to the lights of the town. I can’t prove or disprove this theory.

In the urban environment, the aesthetic value of the trees and landscapes is by far more important than nut production. High levels of unsightly webs distracts from the beauty of the community and for this reason many community leaders have become concerned about fall webworm activity.

In North America, where many of the insects that attack forest trees were accidently introduced from Europe and Asia, the fall webworm is native to North American and Mexico. This pest has been recorded to attack 88 different species of trees which includes most ornamental, fruit and shade trees. In 1940 this insect was observed in Europe and from there it was introduced into Asia . In Europe and Asia the host range has expanded to include 200-300 tree and plant species.

In Texas there are two to four generations per year with the first generation occurring as early as April in south Texas but not until June around Lubbock and Amarillo. Fall webworms overwinter as pupae in silken cocoons under ground trash or in rough tree bark. In the spring, female moths emerge and deposit eggs in masses in a single or double layer on the underside of leaves. These egg masses can contain several hundred eggs and are covered with hairs from the female. This covering of hairs or scales gives the egg mass a fuzzy appearance. which is a means to distinguish fall webworm eggs from walnut caterpillar egg masses which are bare.

Upon emerging from eggs, larvae immediately begin to feed and construct a web. Unlike the tent caterpillars that feed outside of a web, all feeding by webworm larvae is done within the web. As more food is needed, larvae expand the web to additional foliage.

Management of this pest can include both pruning and the use of insecticides. For large trees, most management practices will require the use of an insecticide, however, if a web is located in an accessible or prune able location, webs can be removed and destroyed. Webs that are torn open will provide access to the colony to the numerous predators and parasites that attack this insect.

Over 50 different species of predators and parasites have been recorded attacking this pest. If insecticides are needed, a high pressure sprayer should be used to force the spray into the web. There are numerous insecticides that can be used against this insect. Insecticides containing Bacillus thuringiensis or Bt. can be effective against this insect if applied when the larvae are small.

If webworms have been a problem in your area, be observant and watch for eggs on the underside of leaves and apply some control measure before the webs get out of hand.

If you are concerned about the fact that your neighbor won’t manage this insect and the effect it may have on your trees, don’t worry. Your trees will be free of webs while your neighbor’s trees will be discussed down at the coffee shop.

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 Post subject: WEBWORM 101
PostPosted: Wed Aug 06, 2003 2:42 pm 
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Bill,
Excelent links on the life of webworms. They have been filed.

It would appear that the two articles answered most of my questions.

BT appears to be the best control in the early stages of the larvae begining their feeding. Our infestation began about mid-July. BT should have been applied at that point.

Have opened the webs and the various preditor insects and wasp are doing a good job thus far.

There have been some of the worms dropping from the trees and crawling off. Too full I guess. :roll: Have there been any studies of the crawl-a-ways?

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[The Alamo City]


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