On Apr 25, 2007, Marielouise2 from Tucson, AZ wrote:
These are very destructive pests. At first sign of caterpillars, treat with Bt (bacillus thuringiensis). Caterpillars must ingest the spray; shortly after eating it, they stop feeding and die. This is a biological control and is not harmful to birds or beneficial insects. Bt is available at garden centers.
On Jun 12, 2007, ylwbrd from Chandler, AZ (Zone 9a) wrote:
I have had a Thompson grape vine in my yard for 9 years, and have never had a problem. This year I noticed damage to leaves, and upon closer inspection found the little critters, lined up in circles, devouring the leaves. Some were no more than the diameter or a pin, and others were more mature and about 1/4 in dia. and about 1 inch long. First I sprayed with an organic soap, and had no results. When the BT finally arrived (my local garden centers didn't know what I was talking about), I sprayed, but by then most of the caterpillars were gone. Now my yard is full of the flying insects. Pretty, but I know they will lay eggs and we're off and running for next season.
Does anyone know about what else these guys are hungry for? Do the adults cause damage? Are there any natural predators?
On May 24, 2009, daveclancfamily from Apache Junction, AZ wrote:
a week ago my grapevine was full and beautiful, today there is not one leaf left! I have hundreds of catapillars on there, but i just noticed thousands and thousands of these black dots on the wall next to it. are these eggs?
Is Bt the only killer to use? I really want this infestion gone.
On May 30, 2011, cfusion1 from Las Vegas, NV wrote:
Yes DT is the only method of purchased pest control you can use. The eggs are black pin dots like someone took a pen and inked all your leaves. I have had them two years in a row now (grapes vines are three years old) and this year I am not spraying with DT. There is a non pesticide removal process and it is labor intensive but worth it. In the cool of the morning and evening venture outside and check for the flying blue/black moth. Either spray it to the ground with a strong blast of water or swat it with a fly swatter and kill them as you see them. You will not see all of them, but you will cut down on how many lay eggs. Next look under the leaves of your grapevines for the black dots and rub them out with your gloved fingers. If you miss them and the caterpillars are eating remove the individual leaf and stem to stop them from spreading. Even when the vines have been skeletonized, the plant can be saved, just cut it back and start over. Disheartening, but if you want grapes spray or use the method above.
On Jun 12, 2011, frogymon from Mesa, AZ (Zone 9a) wrote:
Had a real problem with them this year and couldn't find Bt locally, so wound up cutting off worst infected leaves and squishing the rest of the caterpillars by hand. Haven't seen any since it the weather has been consistently in the 90's.