DEAR JOAN: I have several times bought ladybugs for my wife's roses to get rid of the aphids.
I don't put them on until nighttime. I water the plants first, then put them carefully on the plants, per container instructions. And the next morning I can't find a one on her roses.
Any suggestions? We try not to use pesticides and were hoping we could do it with ladybugs.
DEAR TOM: Who would have known? But there are a few reasons why buying ladybugs is not a good idea. You've discovered the first one -- you can't count on them sticking around your garden. You can try caging them around the plant with very fine mesh, but that's an awful lot of trouble and expense when there are so many easier ways of dealing with aphids.
Almost all of the ladybugs available at home improvement stores and garden centers are collected in the wild during hibernation.
The seller extends the hibernation, so when the ladybug wakes up in your garden, it is genetically programmed to disperse. Also, ladybugs in the wild may carry parasites. You may inadvertently introduce this parasite to a region where it didn't exist.
The best thing to do to attract and keep ladybugs in your garden is to plant sunflowers and other plants that produce a lot of pollen. This will not only draw in ladybugs but also other beneficial insects.
As for the aphids, ladybugs and green lacewings will take care of them, but you can help by simply scraping them off the stems with your fingers (I wear gloves) or setting your hose nozzle to "jet" and blasting them off. Once they are on the ground, they aren't very good at climbing back up to the new, tender growth. Also, as it gets hotter, the aphids tend to die off.
Because they are so easily controlled, I don't recommend pesticides. Be careful, too, when using rose food. Some of it has a systemic pesticide in it that, in effect, makes the plant poisonous to the insects munching on it.
That sounds like a great idea, but it also can wipe out bees and other insects that collect the pollen.
DEAR JOAN: I'm in an 80-member community garden surrounded by a chain-link fence. Resident rats that live in our compost and storage structures right next door are procreating quickly, sustained by our tasty veggies.
We understand that survivors of baits have evolved to only take several nibbles out of each of our veggies, ruining a lot of tomatoes, cole crops, berries and anything except onions, so far. We hesitate to use poisons but wonder if baits on snap traps would work considering the tastier alternatives.
DEAR JEAN: Rats breed at a much faster rate than even rabbits, so a small problem can quickly become a big one.
Please do not use baits or poisons. These are not safe as other creatures -- birds, foxes, coyotes, dogs, cats -- can also be poisoned if they eat the dead or dying rats. And poisons around a vegetable garden are risky.
Rats are opportunistic feeders and will go for your baited snap traps as well as your veggies. Bait with peanut butter or walnuts. If you use snap traps, place them beneath overturned boxes with a small opening cut into the side so that birds and other creatures can't get to them.