The local climate seems to have produced a banner crop of aphids this year! For us gardeners, a good year for aphids can be a bit of a problem. You can purchase commercial non-toxic products like insecticidal soap that will kill the aphids. Because these products are fairly expensive, I recommend saving them for the hardier pests like squash bugs and mounting a cheaper attack on the aphids. This article from last year details some of those less expensive methods.
By closely observing the aphids over the years, I have learned that in most instances you need to do nothing. Often, soon after you notice the aphids, ladybugs and other insects will show up. It seems that both the adults and their larvae eat the aphids. Most years, other than a quick attack on an aphid covered rose bud or kohlrabi plant, I don’t have to worry about the aphid population. But, when it does get so bad that I need to take action, my weapon of choice is the garden hose. By hitting the population of aphids with a strong, fine spray of water, I knock them off the plants to the ground. Surprisingly, even with the help of the local ant population, they do not seem to be able to find their way back up to continue dining.
For hardier insect pests than aphids, I have found that using 2 tablespoons of a biodegradable, phosphate free, soap in a gallon of water kills pests like earwigs and squash bugs. This soap tends to be cheaper that the commercial gardening products sold for the same purpose. The trick is that you actually need to get each insect with the soap. Because there is no residual effect, (a good thing), any bug you miss will live on to eat another day. This is not really a problem because even if you can’t kill every squash bug, you usually can reduce the population to a level that will still leave you with an abundant harvest.
Squash bugs are fairly easy to spot when the plants are young, but if you have a large garden of sprawling pumpkins it can be very time consuming trying to hit every bug with the soap. Still, don’t consider for a moment succumbing to the alternative of using a broad-spectrum insecticide and killing all the bugs, good and bad and poisoning your garden. I usually plant more pumpkins and squash than we need so when the occasional vine is killed by the bugs, it is not a problem for the overall harvest. I reproduced a short article I wrote a while ago specifically discussing squash bugs.
Earwigs seem to do their dirty work at night, on young plants, so I attack them in the dark with the soap spray and a flashlight. Once the plants get to a larger size, I forget about the earwigs and they don’t seem to do any further damage. Earwigs, along with many other pests like slugs and snails, can also be effectively controlled by spreading diatomaceous earth around the base of plants.
Spotted, (and some striped), cucumber beetles are another pest that enjoys residing in my organic vegetable garden. Although they do make small holes in the leaves of my plants, they seem to do their real damage by spreading a disease that can cause certain plants to die. In my garden, in addition to living on squash and pumpkins, they seem particularly attracted to bean plants. I have found that because they have such large populations, and can fly so well, they are hard to control.
I notice the cucumber beetle creating problems in two ways. When the beans are just emerging from the ground the larvae can eat the top bud of the bean plant, killing it. To help with this problem, I plant two or three times the seeds I need around each pole. If the emerging plants are attacked, I still will usually be left with several vines that survive. If a particular pole bean escapes attack, I then just thin the seedlings to the number I want around each pole. Interestingly, this year I had a couple hills of beans that had 100% mortality on one side of the pole, and 100% survival on the other. Strange! They don’t seem to cause a problem for my bush beans. This is probably because I plant bush beans very thickly and their growth pattern does not provide a long enough time for the beetles to kill the plants. My bush beans mature rapidly in the summer heat, produce a heavy crop of beans and then are done. The second problem caused by these bugs is on the mature pole bean plant. As the plant gets older, it seems less able to resist the disease the beetles transmit. By this time, however, I have usually harvested 80 or 90% of the beans that the plant is going to produce. So, I live with the beetles and still seem to get a decent harvest of beans.
I have heard of some organic gardeners using rotenone to control cucumber beetles. I do not agree with this practice. Just because Rotenone is a "natural" rather than synthetic insecticide does not, in my opinion, make it safe.