Nasty Cutworms- Squash Vine Borer
Zucchini in Texas is a lot of work. We have these nasty little moths that look a lot like orange wasps. They lay their eggs (see above picture) on zucchini stalks. The little worm that hatches bites into the stems and begins to eat the plant from the inside out. Yeah–science fiction in the real world. This year I tried injecting the plant with BT worm killer. I had no real way of knowing it if was working or not.
Two weeks ago, I saw one of the parasites (moth) land on my zucchini. I managed to kill it. Had it already laid eggs? I had no way of knowing at the time because I didn’t know what the eggs looked like. I injected the stalks again as best I could and began to watch. Had I known what the eggs looked like I could have knocked them off. They aren’t that hard to remove because unlike a lot of other insect eggs, they aren’t very sticky, and they are actually pretty easy to see on most parts of the plant.
Today, I saw frass–this is basically worm poop that squirts out the entry holes when the worm invades. Sigh. I began cutting the stalks from the main stem. My hope was that I could cut the leaves/stems off before the worms worked their way to the main stalk. Once they are inside the thick, main stem, injecting BT worm killer is almost impossible–and so is killing the worms. Within a few weeks they will eat the stem out and the plant will die. I found one spot with worm poop where it looks like a worm made its way in. We’ll see, but I don’t have very high hopes. I also found several more eggs which I removed.
On the bright side, I do think the BT worm killer works. There were some leaves/stalks where the worm did a bit of damage–but then the damage stopped and there was no worm. The leaf continued to thrive. I cut a couple of these leaves off and inspected them pretty carefully.
The overall problem is larger of course. The moth lays so many eggs (I found about 10 tonight, about one per leaf) it’s impossible to find all the worms and kill them in time. The eggs are much harder to see near the soil or on the main stem.
At any rate, I did better this year than last. I have had zucchini now for about two months–at least 3 zucchini per week. I don’t expect the plant to live much longer, but at least the moths are infecting it rather than the cucumbers and cantaloupe. I’m afraid that if I didn’t have the zucchini, the moths would use the other cucurbits as a substitute! I’ll be planting early again next year. It seems to have helped that the plant was quite large by the time the moths began looking. (They started late April or early May and then continue throughout the summer in Texas.) I’ll also be vigilent about looking for those stupid eggs.
Here’s a picture of a moth–I didn’t take it because when I see them, I kill them if I can. I tried to make sure the credit for the photo showed up.
Update: I’ve had a lot of questions about cutting off leaves and or the leaf stems and whether it will kill the plant: Yes, you can cut some of them off. I have cut several away as time has gone by–the worms entered the stems of the leaves and left evidence. If they are close to the main plant stem, I definitely recommend cutting the whole leaf/stem away from the plant. If they are not, you can inject the BT worm killer into the hollow leaf stem. The BT worm killer does seem to work after about a day.
I also inject the bt worm killer into any infected parts of the main stem. It’s hard to do because the main stem is not hollow, so you kind of have to hunt out the part where the worm has eaten it away. At this point, my plant stem is large enough that it has withstood two or three worms–so if you see frash (worm poop!) don’t give up. Try the BT worm killer, try to follow the path of the worm with a thin, sharp object and kill it.
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Man, I sure it is not as hard here in Arizona! I know we have some things to worry about, insects wise, but I am looking forward to trying to defend out plants!
Only a little over four months to go and I (Well, we. That is when Ashley and I are getting married) will have my(our) house so we can have our own garden! We are so excited!!!
Comment by Patrick-FBS — June 22, 2008 @ 2:45 pm
Congrats–I know you’ve been looking forward to getting married and settled! Yeah, AZ is drier so you actually have less bugs. There will be some problems and maybe you’ll have to worry about birds now and then, but my parents in NM don’t have nearly the problems that I do (they don’t have the moths for one.) NM gets decent freezes and cold so a lot of the bugs do die off. Texas can have times where we barely freeze once or twice.
This year has been beastly hot and very early this year. I’m watering out the ying-yang–as if I lived in Az.
On the bright side, the zucchini plant hasn’t died yet! I’m trying to get part of the main stalk to root (they kind of fall over and wind up and down). With another spot rooted, the thing should be good to go for a while yet!
Comment by Maria — June 22, 2008 @ 3:05 pm
I feel your pain, Maria. Only it’s tomato-flavored. I’ve picked three tomatoes so far, and every single one of them have had some kind of worm hole in it.
I’ve checked the entire plant thoroughly-no sign of worms, insects, whatever, and the overall plant looks very healthy.
Very frustrating.
I had to buy tomatoes this morning from Wal Mart. That’s just not right.
Comment by Trina — June 29, 2008 @ 2:08 pm
That’s a different kind of worm–and fairly easy to kill, I think. Get some BT worm killer. Spray the whole plant–it kills only worms, nothing else. It’s very environmentally friendly. I use it for tomato hornworms (and that is one ugly worm.) I think the worm giving you problems is probably a little brown one and it comes out at night. You can take a flashlight and look, but it’s easier to just spray the plants. They may get a couple more of the tomatoes, but BT worm killer should stop them.
If you have it, you could also surround the base of the tomato plants with a row of copper (like cut up a copper scratch pad). A lot of insects don’t like copper and the sharp edges of the copper cut some insects and kill them (they dehydrate).
It’s a battle to keep these plants going, that is for sure. The zucchini will likely succumb by the end of the day. The inner part of the plant started wilting last night, but I couldn’t find the entry hole in the main stem. I found it finally this afternoon–along with clearing ANOTHER 10 eggs off the stupid dying plant!!!! I squirted BT worm killer into the stalk, but I think this one is a gonner. I’m just hoping that as the worm eats all day, it gets a mouthful or six of the worm killer so it never makes it out of the plant to moth stage.
I’ll know by morning if the plant can make it. About half of it is severely wilted so I’m guessing I got the last of the zucchini out of it. I had a decent year considering–2 or 3 months of production.
Comment by Maria — June 29, 2008 @ 2:39 pm
Thanks for the tip. I’ll try to get out this afternoon and see if this hardware store across the street has BT.
Comment by Trina — June 30, 2008 @ 7:53 am
I hope it works for you. Luckily it won’t hurt!!!
The zucchini plant is actually still alive–we got rain last night which cooled things down 20 degrees (to 72, the coolest it has been in probably 2 weeks.) Unfortunately we’re scheduled to be 92 today and 99 tomorrow so unless those worms stop eating really soon…
Comment by Maria — June 30, 2008 @ 8:08 am