Pest Control

Sliema, Malta

I have noticed that caterpillars are eating all my salad leaves which are growing in containers. I had seen the orangey stuff on the bottom of some leaves, but did not know what it was. Apparently the white butterflies lay eggs, and these then hatch into caterpillars and eat the entire plant (as I have not learnt!). I was thinking of using an organic pesticide. My local nursery has suggested Bayer Organic Pest Control. Is this safe to use on edible plants? Thanks.

SE Houston (Hobby), TX(Zone 9a)

Sound like you're growing squash, and have encountered the dreaded Squash Vine Borer, which leaves the orangey "frass" as evidence it has bored inside of your vine stems.

There's a whole thread on the Vegetable Gardening forum dedicated to discussing ways to prevent this pest from destroying this year's squash crops in our gardens.

I invite you to come read through the current posts, and re-post your question above on that dedicated thread.


Irving, TX(Zone 8a)

I will not use Bayer on your lettuce. Is that the lettuce you showed pictures a while ago?
I'd just spray some soapy water and try to remove those little caterpillars with your hands ... if I remember correctly: you didn't grew many plants ...
Also you can move your container in a different location and see if it will help.
I don't use/spray anything on my vegetable garden ... that is the point on growing your "own" food right?
Good luck

Efland, NC(Zone 7a)

Mornin', Folks...
A rare treat for me to get on DG this time of year. However...

"Sound like you're growing squash, and have encountered the dreaded Squash Vine Borer"

Actually GG it doesn't sound like that at all. MonkeyFlower mentioned "white butterflies" and those would be the adult form of one of the several cabbage worms (cabbage worm, looper, or diamond back). The orangey stuff on the bottom of the leaves are the eggs which will hatch out to a gazillion babies. (Squash vine borers lay their eggs at the base of plants so the larva can enter the stems; and they don't eat the leaves, as MonkeyFlower mentioned was what was being eaten on her plants.)

MonkeyFlower, I haven't used Bayer Organic Pest Control but since you are zeroing in on one particular bug, and know w/out a doubt it is a worm, you might want to use a Bt product, specifically geared towards the caterpillars. Dipel (powder) or Thuricide (liquid) are two of the most popular brand names and will zap those caterpillars w/out killing off any beneficial bugs.

Regarding Bayer Organic Pest Control, read the label if you choose to use this. It may certainly be safe to use on vegetable crops but there may be a waiting period after spraying it before your crops are safe to eat.

Happy Gardening!

Sliema, Malta

Hi, thanks so much for your replies, yes I'm referring to the pics I posted a while back. I had a 40cm long container with about 15 different seedlings and they're all gone! I have a couple more containers with salad leaves growing and I'd like to do my best to save them.

I agree with drthor on the fact that the whole point of growing my own stuff is not to spray anything on them, so I'll try the soapy water method, and also try and remove the leaves with orange eggs on them.

I was also going to try and get my husband to build me some sort of protective cage out of netting and bamboo sticks which I can put over my containers and just lift to water. The butterflies shouldn't be able to get through that.

Thanks once again for all the helpful replies, very much appreciated! :)

SE Houston (Hobby), TX(Zone 9a)


I stand corrected (again)! Read his post on the fly! Will read more carefully in the future!



Charlotte, NC(Zone 7b)

The best organic, free pesticide I've ever used to kill butterfly eggs and their caterpillars is my thumb and finger! Just squish them.

Invite birds and wasps to your garden, they'll eat the caterpillars you miss.

Delhi, LA

Dr. Bader's Pest Book says the moth of a cabbage looper is brown with silvery wings. The loopers are light green with tiny white stripes. The remedy is to sprinkle corn meal on the plants. The looper will eat it and soon die. If one catepillar eats corn meal and dies, I don't see why it wouldn't work on others as well. Be cheap to try and probably right at hand.

Sliema, Malta

I'm still having problems with the caterpillars. I've tried soapy water but doesn't seem to help much. Also tried looking for them, but I'm at work all day, so that doesn't really work for me. I'll try sprinkling cornmeal. Not sure I've seen that in the supermarkets though. According to Google, it is also known as polenta or maize flour, so I'll try that! Really hope it works as my salad containers are slowly being eaten away. :(

Irving, TX(Zone 8a)

So sorry about that.
In many cases bugs attach when the plants are weak. Is your container on the sun or shade?
What is your day/night temperature right now?
if you help me to understand your weather condition I might be able to help.

Also, here is a rule on how many seeds you need to plant next time:
1 for you
1 for the wind
1 for the birds
1 for the caterpillar
1 for the neighbor that is your friend only when she knows that you are growing vegetables

Sliema, Malta

My container is in a south facing balcony - it gets morning sun and then it sits in bright shade for the rest of the day. The days are now getting warmer (around 18 C during the day and maybe 12 C at night). Not sure your rule works though - they went through one whole container and left nothing but stems!!!

Irving, TX(Zone 8a)

Wow you lettuce must be delish !
My lettuce is in full sun right now ... maybe you want to try to move your container around ...
Your temperature is perfect for the lettuce at this point.

Plantersville, TX(Zone 9a)

I would move the container indoors when not at home. Are they eating it during the night, or during the day?

Sliema, Malta

I've just scattered polenta all over my salad leaves after coming home from work and finding about 10 caterpillars and a couple of leaves with larvae on the underside. In fact, was thinking that the best solution was to try growing them indoors, next to the patio door, with the blinds partially open. I'm also growing cherry tomatoes, strawberries and head lettuce - I hope they won't be attacked too!! I can't keep everything inside!

Contra Costa County, CA(Zone 9b)

Sounds like a mesh over the planted area(s) could be the answer.

The adults of the caterpillars fly, so a mesh that keeps everything off the plants will exclude the moths that lay the eggs.
The arches can be almost anything, but I use the plastic pipe sold for irritation, PVC. It is sturdy enough to stand up to a meter high, for the larger plants, and is reasonably resistant to rotting in the sun. (Not totally resistant- after several years it will shatter, if bumped.)

Sliema, Malta

Sounds like a good idea too, Diana, I guess I can also use bamboo sticks for support. Would bird netting be ok, or should I go for something with smaller holes? Thanks.

Irving, TX(Zone 8a)

which soil did you use?
could these caterpillars have come from the soil you used in your containers?

a picture could help.

SE Houston (Hobby), TX(Zone 9a)

A couple weeks ago, I started hardening off my bell pepper seedlings. I'm using "tulle" (the wedding veil material) to cover them, and it's working like a charm! You can purchase it at your local fabric shop. I bought a bolt online for roughly $50 (including shipping). It's 9' wide by 108' long, reusable, and will last a lifetime in my garden!

I wasn't sure it would work until I spied a cutworm? moth (3 black dots on the greyish moth) caught up on the OUTSIDE of the tulle, and later spied a STINKBUG (again, on the outside), trying to figure out how to get to the bell peppers!

When I sow my seeds this weekend, I will cover the RB with the tulle and either tack it to the sides of the box, or, anchor it down on the soil with landscape pins (which you can make out of old metal hangers to save $$).

I'll be growing zucchini squash in two large (25 gallon) containers. I plan to form a criss-cross pvc hoop over them then drape the tulle over the hoop to keep the Squash Moth from landing on the stems. If she can't land, she can't lay eggs for the Squash Vine Borer! Once the squash starts producing blooms for pollination, I'll remove the tulle so the pollinators can move in. Hopefully, the plants will be big enough at that point to stand some hits from the moth, because I know I can't stop them all. But, I can sure slow her down!

At this point, you'll need to squish and hand remove as many caterpillers as you can find. Try doing this at night, using a flashlight. You'll be surprised what you'll find that comes out in the nighttime! Then, buy a couple yards of tulle and drape over your plants. Monitor your leaves for any cats you missed. At least you'll interrupt any more moths laying eggs.


Sliema, Malta

@ drthor: I always use fresh compost for each container. I remember seeing yellow bubble like things on the underside of the leaves but didn't know what they were. I stupidly thought it was some kind of pollen! Then I read that it's the larvae of the white butterfly, which I've seen regularly in my balcony.

@gymgirl: I'll try the tulle, but need to have it removable. How do you water the plant if it's permanent?

I only found one caterpillar when I got home today, I'm hoping the cornmeal method will work!

SE Houston (Hobby), TX(Zone 9a)

I hose/water right through the tulle.

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