Garden bugs

June 23, 2009 9:34 AM

I have some questions about pest control in the garden, coupled with mysteriously disappearing plants.

This is our first year attempting a real live vegetable garden - finally have a small back yard, so we built a raised bed, filled it with dirt, and planted some vegetables. We also set up a composter and put some plant boxes on the apartment balcony.

There are lots of bugs, and I'm unsure which ones are ok to leave alone and which need to be taken care of. The composter has attracted LOTS of (mostly fruit) flies. There's a big swarm of flies every time I open the lid. Is this normal? Do I need to adjust our use of the composter in some way to get rid of them?

I've also noticed ants in the raised bed. I think there's a nest in or around the bed, but I don't see any mounds; I only noticed them when they were busy dismantling a dead earthworm. Are these an issue? They're small and black, and they don't seem to be bothering the plants. Other bugs I've noticed in the dirt are earthworms (I'm assuming these are ok) and some sort of larvae - they all seem to have disappeared over the past couple of weeks since they've probably all metamorphosed and flown off as whatever they were.

Coupled with the bugs, some plants have gone missing. They're all still pretty small, and about three or four have simply disappeared. The MO is the same each time - a small divot where the plant was, and a couple of instances I found the plant, neatly cut at the base of the stem. Any ideas what could be destroying our plants in that way?

posted by backseatpilot to home & garden (16 answers total)

Re: the fruit flies. Presumably, you're putting food scraps into your compost bin. If you're getting too many fruit flies, that means your proportion of food scraps : brown materials is too high. Don't worry about the ants, unless you've got bajillions of them. If you have that many, you need to add more water to your pile.

Re: the missing plants. I don't know about divots, but do you live in a subdivision in the 'burbs? When deer chow down on my plant, they bite down fairly low on the stems, and it looks like somebody had trimmed off the stem and leaves with scissors.
posted by joyceanmachine at 9:40 AM on June 23, 2009

We had a problem with rabbits early in the spring - about half of our sunflower seedlings got eaten. I put an impromptu fence around the others and managed to save them. Our garden bed, such as it is, has had a mesh fence around it from the get go for just this reason.

The big bad bugs in gardens are things like aphids, cutworms, and squash-vine borers (if you're growing any squash-like things). Other things to watch for are fungi, blights and various viral infections. Some of these can be treated, others are pretty much death.

Your local county extension office is the place to go to find out what's bad for your area and what's not, as well as what to use for treatment. There is a good list of beneficial bugs here.
posted by jquinby at 9:40 AM on June 23, 2009

Your missing plants are probably rabbits or squirrels or chipmunks.

Ants can be a sign of aphids. Aphids are itsy little bugs on the underside of plants that suck the juices from the leaves. They leave behind a sticky substance that ants lurve. Do you get a little cloud of light-colored bugs when you shake the plants?

Earthworms are awesome.
posted by desuetude at 9:55 AM on June 23, 2009

Fruit flies are natural attendants of compost bins--their larva help break down the scraps--but you can reduce the number by covering kitchen scraps with lawn clippings.

Cutworms are probably what's getting your little plants if the tops are left like warnings to the rest! though occasionally, birds get carried away hunting worms and snip the stems of plants, particularly if the stems are red-tinged; I guess they look like worms. Hey! Birds have brains the size of your thumbnail; give 'em a break.
posted by miss patrish at 10:01 AM on June 23, 2009

Cutworms chew through tender young stems at the soil level. They look like (because they are, I guess) grubs. Put collars made of small paper cups or tuna tins with the top and botttoms cut off around the young plants. Some say standing a 16d nail tight to the stem will work. jquinby, above, has good information.
posted by Hobgoblin at 10:01 AM on June 23, 2009

Regarding your compost, the best way to reduce fruit flies is to keep a pile of brown material beside the bin (leaves are not so great, dried grass clippings are good, some old hay or straw is even better because it allows better air circulation). Food scraps just sitting out in the open are going to attract flies, so every time you throw some in, make sure to cover them with brown material. You can also add a little fresh-ish manure on top of the food scraps or even a little dirt if you still can't keep the flies away.

Regarding your disappearing plants, it sounds like some type of critter is getting into your garden. It is pretty hard for anyone here to say what sort of critter it might be, but assuming it isn't deer (you wouldn't find the plants cast aside if it were), a short mesh fence will likely solve your problem. You can attach some posts to the corners of your raised bed and attach some plastic mesh easily.

It might be helpful to know what type of plants are disappearing.
posted by ssg at 10:06 AM on June 23, 2009

keep a pile of brown material beside the bin (leaves are not so great, dried grass clippings are good)...

Just want to point out that dried grass would be a 'green' (nitrogen source), not a 'brown' (carbon source). If you've already got too many food scraps in your bin, adding grass clippings isn't going to help. And dried leaves are find if they're shredded or crumbled. Whole dried leaves do take a long time to break down, though.

I think w/r/t the fruit flies in the compost, you should probably make sure that you're covering up the scraps with your leaves (or whatever you're using as a 'brown'), and turn the compost more often than you're doing. Also, keep it damp, but not wet.

Seedlings gone missing -- agreed, it would be very helpful to know what kind of plants these are. If they're tomatoes, peppers, cucurbits -- in other words, plants that aren't themselves edible, but which produce edible fruit -- it's going to be one group of possibilities. If it's lettuces, peas, herbs -- plants that are themselves edible -- it might be another. The good news is that if they're in raised beds, it's probably not moles or gophers. Another possibility that hasn't yet been mentioned is sparrows or other songbirds. They completely devour my beet, lettuce, and pea seedlings every fall if I don't cover the plants.

Ants are nothing to worry about, unless they're aphid farming. Worms are your friend. Certain grubs just lie in the soil waiting to turn into something else, and others lie in the soil eating stuff. If they're gone, well, you don't have to worry. Just watch for moths or other things that could be part of the next cycle.
posted by mudpuppie at 10:29 AM on June 23, 2009 [1 favorite]

After my third round of broccoli, cauliflower, and brussels sprouts where chewed off to the ground this winter with the chewed off bits gone, I covered everything with bird mesh and tried to clip it down as well as I could (I use binder clips from the office supply) to the raised bed edges. One spot was a little uneven, and my mystery critter got underneath, chewed off a foot tall brussels sprout stalk, and then couldn't get back out from under carrying it. I found the stalk yanked about a quarter of the way through the mesh and then abandoned. So mesh works, but you have to seal all entry/exit points.

You mostly don't have to worry about bugs until you see them chowing down, or you have holes on plant leaves (slugs and snails are nocturnal, I just put out Sluggo pellets whether I see the little bastards or not). The biggest pest I've had trouble with are cabbage worms on cole crops (the aforementioned winter veg in particular), which can eat a bed of broccoli down to stems in a couple of days. They are exactly the color of the vegetation and you can look 10 times before you see them, but they are primarily early spring pests (then they turn into pretty little white moths that lay eggs that come back and wreak their havoc again). I did not find anything organic that would nuke them, but I now have some Bt on hand for next time.

It's hard to have a raised bed without some ants, because it's so cozy for them. As long as they aren't fire ants and there's not a huge population, I just leave them be.
posted by Lyn Never at 10:50 AM on June 23, 2009

I've been surprisingly lucky with something my mother told me to do--clumps of llama dog's fur around the plants and garden. Despite the crazy number of deer, rabbits, and other salad bar regulars, no one has eaten our romaine lettuce but us.

I assumed, as with most of mom's advice, that's I might say a quick incantation and get the same results, but it worked.
posted by A Terrible Llama at 10:54 AM on June 23, 2009

Can't answer missing plant question as the only critters I've had probs with are big lazy cats who like to nest in the the garden and squash things.

Pest control:
- green onions, marigolds, anything with a strong scent in between your plants is good. Look for books by the woman who wrote Carrots Love Tomatos for info on companion planting to make your garden unattractive to pests and to keep your plants happy. Some work together better than others.

- scatter dried egg shells around anything that attracts slugs

- a blast of water will dislodge a lot of pests; or, use my grandfather's remedy for soft bodied pests: whip soap or detergent (but soap is better) into a pail of water with a small whisk, then use the whisk to slosh soapy water onto your plants. It coats the bodies of the soft bodies insects and basically smothers them. Repeat after a strong rain.

- make sure your plants have air circulation by pruning out dead leaves, suckers on tomatos as breezy conditions dry the plants (no mold), and move along insects

- some people hand pick bugs; I just can't

- if you do get an infestation on a single plant, sacrifice the plant or whatever part of it is infected. Do not put the plant in your compost.

Compost: Perhaps a simple tube for air would help. I used to keep a piece of pvc pipe with holes drilled up and down it in the centre of the pile to let a bit of air in there. And, I always had some leftover dirt to scatter on top of the leaves and other stuff.
posted by x46 at 12:26 PM on June 23, 2009

Thanks for the info. I'll check for aphids once the rain stops, but I don't think I've noticed any up to now. I'm not sure about small furry critters, though - we live in a pretty urban area, and I've only ever seen the occasional squirrel or two. Deer have been making their way into the city lately, but the yard is completely fenced in.

One issue with the compost - the yard is so small it doesn't generate enough brown matter. I had a whole garbage pail full of leaves, but the landlord hired a landscaper to touch up the property and he took all my leaves away with him! Can cardboard/newsprint/something else stand in for leaves and twigs?
posted by backseatpilot at 12:53 PM on June 23, 2009

Oh, and the plants that went missing were tomatoes, basil, and a baby zucchini. Lettuce, parsley, and peppers have all been unmolested. The cucumbers had what looked like some scalloping around the edges of the baby leaves, but the mature leaves look untouched.
posted by backseatpilot at 12:54 PM on June 23, 2009

Can cardboard/newsprint/something else stand in for leaves and twigs?

All of the research I did points to yes, but you have to shred the stuff pretty finely first and/or create a slurry out of it by soaking it in water for awhile.

I'm in the same boat - no browns in any sort of quantity until the fall. I way overdid it with greens and it turned into a stinking mess, even with frequent turning. It did get hot as can be, though - steaming pretty hard even on warm days. I'm battling the fruit flies too and will probably layer some grass clippings on there the next time I cut the grass.
posted by jquinby at 12:58 PM on June 23, 2009

Here's a good list of browns - shredded (non-slick) paper and cardboard can help you balance your compost.
posted by Lyn Never at 1:03 PM on June 23, 2009

I wouldn't use newspaper, personally. Too many chemicals, and too much clumping potential. People do, though, so go for it if it sounds like an option that will suit you.

Does your municipality pick up yard waste? That's the easiest way to get leaves -- drive around and pick up other people's from the street. If that's not an option, you could by some shredded bark mulch (the shredded-er, the better-er). It'll break down more slowly than leaves, but if you get the finely shredded kind, it should be okay. And honestly, if you're just composting to reduce waste, that's a perfectly fine option. If you want a speedy way to make soil amendments, it's probably not the best route, because it's going to take more time to end up with a finished product.

The missing plants -- it's starting to sound like cutworms to me. More info here.
posted by mudpuppie at 2:15 PM on June 23, 2009

Aaargh, cutworms. I am battling them right now. What you are describing is exactly what happens - the plants either just disappear, if they're little, or are cut down at the soil line if they're bigger. If you dig around the cut plant in the morning about 2 inches deep, you'll usually find the little asshole cutworm that did it, and then you can squish him.

Somehow my gardening experience has turned from seeing what I can grow to seeing how many of these bugs I can destroy. It's depressing, but I will not let them win.

From the pictures in the links here I have black cutworms. I've taken out at least 25 so far, and I suspect there are more hiding in there. The collars really do work - I make a collar out of a 2L pop bottle - cut off the bottom and the top and then cut the tube in half to make 2 collars.
posted by Jupiter Jones at 5:44 PM on June 23, 2009