Early action needed for whiteflies and aphids?

Question

While pruning my tomato plants last night, I came across some early signs of whiteflies. I saw just a few mature whiteflies crawling around; I hate them. I have battled them off and on through the years with various crops. While looking at the underside of some of the leaves, I only noticed a few spots where eggs were attached and also a few pink soft aphids I thought. I cut those branches off of the plants to dispose of the eggs.

I have a raised garden bed housing just some lettuce, peppers, and tomatoes; maybe 40 square feet. Do I need to go into full "kill mode" and spray for these pests or is a certain amount of infestation just expected to occur? I don't want a full blown attack from these pests but I also don't want to jump the gun if it is not needed.

On the same topic: I raised tomato plants from seeds this year for my first time. They are so much healthier than purchased plants and I am very pleased. What are the odds that these pests just showed up on their own? The pepper plants were the only plants purchased from a nursery. The lettuce was also grown from seed.

Answer 1

Pests like aphids just appear brought in by the wind normally, and then setup in an area by laying eggs on trees, fallen leaves to survive the winter. However, I have seen basil plants being sold by an organic shop that was infested with aphids. A shop that specializes in selling plants is less likely to sell you infected plants.

There are a number of strategies to deal with infestations but since they rapidly multiply, you need to deal with them straight away. Sticky traps give you early warnings of what you are dealing with.

If it's a very early infestation then removing the whiteflies by vacuuming them up in the early hours of the morning while they're less active and removing their eggs by syringing with water might work.

I used to destroy leaves heavily infested with aphids but now if I see that some of the aphids are parasitized by wasps, I am putting the leaves into a jar so that the wasps can hatch and kill the aphids for me, and the aphids won't be able to crawl from the jar onto other leaves. Time will tell if this is going to work. Any ladybirds I catch I also place under my netting to help with aphid control. But I don't buy ladybirds as I don't wish to risk bringing in ladybird diseases into my garden.

Answer 2

While you don't want to seem as if you're jumping the gun, it's best to take drastic actions before things get out of hand. There are various methods you can try out. Trying introducing predators (or beneficial insects to your garden). If that option repulses you, use insecticidal soaps and water to wash them off.

All the best.

Answer 3

In my experience, pests attack shaded plants a lot more than plants in full sun. So, giving them plenty of sunlight will probably help.

Making sure they have enough (not too much) potassium, calcium and silica should also help to increase the insect and disease resistance. Make sure the nitrogen is balanced with the potassium and probably the calcium levels, too. If you get too much nitrogen, the potassium probably won't do its job well. If you get too little nitrogen and too much potassium/calcium, the plant will grow slowly and if severe, may actually be more susceptible to disease.

Some kinds of aphids are a much bigger problem than others. Some can devastate peppers, I've found (and some hardly touch them). I had some that blew in with the wind on our Ethiopian eggplants last year (but after we tried dousing the eggplants with cayenne, they spread to the peppers, too). They were large, fast, armored aphids that bred really, really fast and wouldn't let the peppers grow. When I fertilized with a foliar spray of calcium nitrate, they didn't like the peppers so much anymore (but the ladybugs, which came and ate the remaining aphids, didn't mind). I imagine a foliar spray of sea minerals might repel pests (since they're salty, and these pests like juice; they might dehydrate with the spray concentrated on the leaves). I haven't tried it, yet (just in the soil, which peppers like), but it's a hypothesis. Sea minerals in the soil did strengthen my indoor potted pepper against its spider mites infestation, and it did eliminate a fungal infection it was suffering from. It didn't eliminate the spider mites, though, unfortunately (but they're not as much of a problem).

As far as aphids on tomatoes go, we only had black, winged aphids on them, and not in large numbers (they weren't a big problem).

Some people talk about using cayenne against aphids, and although it works temporarily, if the aphids are bad, they'll probably bounce back from it with a stronger taste for peppers. Diatomaceous earth might help to control them, but not to get rid of them.

You might consider growing Solanum galapagense, which is supposed to have whitefly resistance. Whiteflies don't bother my tomatoes terribly, though. They seem to prefer other plants in the area (including grapes, Ethiopian eggplant, and peppers, especially the Early Jalapeños we grew).