Everyone has a particular garden enemy that just drives them crazy, this includes the staff at Survival Garden Seeds. When discussing our personal garden challenges at a recent staff meeting, we all agreed that there are 3 insects that are common problems for all of us. Cucumber beetles, tomato hornworms, and Japanese beetles have plagued all of us at one time or another. We thought we would share some of our tactics for dealing with these garden pests.
Nothing is more disappointing than finding your entire cucumber crop decimated by cucumber beetles. If you see holes and yellowing or wilting leaves, you might have a cucumber beetle infestation. Depending on your location you may encounter one of three different types of cucumber beetles - either the yellow-striped cucumber beetle, the yellowish-green banded cucumber beetle or the yellowish-green spotted cucumber beetle. All are incredibly harmful to your cucumber crops and can be difficult to get rid of.
Cucumber beetles lay their eggs near the base of your plants and start munching on your plants' leaves upon hatching. A large infestation can decimate the foliage of a cucumber plant causing defoliation that can weaken and even kill the plant. Not only do these pests feast on the leaves of your cucumber plants, but they also carry several bacterial diseases that they can transfer to your plant, eventually killing it. They will also happily munch on your melons, pumpkins, and squashes.
How to Control Cucumber Beetles
One of the first things you should consider when trying to prevent cucumber beetles is crop rotation. Cucumber beetles can overwinter in your garden soil, so it is important to rotate the location of your cucumbers (and other cucurbits) every year. Till your garden late in the fall to further help expose beetles to winter conditions to help kill them.
Fabric row covers, are probably the best preventative measure you can take. This prevents the beetles from landing on your plants and laying eggs; however, you will need to remove the covers for several hours each day when your plants bloom to allow for pollination.
Nasturtiums are a known companion plant that will help repel cucumber beetles. Interplant nasturtiums between your cucumber plants. They will help keep beetles away and have the bonus of being beautiful and edible too!
Getting rid of cucumber beetles once they have landed is tricky because they can fly off when you’re trying to manually remove them. You can try picking them off while wearing gloves coated with petroleum jelly. Sticky traps at the base of your plants are helpful. You can also shake the leaves of your plants to get the beetles to drop onto something sticky or a bucket of soapy water.
Chances are, if you’ve grown tomatoes, you’ve encountered tomato hornworms. They are a large pale-green caterpillar with white and black markings and a distinctive horn-like spike at its rear. These caterpillars are the larvae of the sphinx moth (also known as the hummingbird moth) and can be up to 5 inches long. While they might look dangerous, fortunately, they don’t sting or bite. However, they have a voracious appetite and can ruin a tomato crop in record time. They can also affect other plants in the nightshade family like eggplants, peppers, and potatoes.
In spring the moths lay eggs on the underside of leaves that then hatch into the caterpillars, which is usually where you will find them on your tomato plants. If you see leaves with large holes, missing flowers, or even scarred fruit, you may have tomato hornworms. If the hornworms eat too many leaves from your tomato plants, you can end up with sun scald damage on your tomatoes.
How to Deal with Tomato Hornworms
Prevention begins with tilling your garden soil at both the beginning and end of the season. This will generally destroy any over-wintered larvae. Companion plants such as dill, basil, and marigolds are known to keep hornworms away. Certain species of wasp larvae will feed on tomato hornworms, so having wasps in the garden is a good thing. Other beneficial insects like ladybugs and green lacewings feed on young hornworms and eggs.
Fortunately, due to their size, tomato hornworms are pretty easy to remove from your garden once you discover them. You can simply pick them off of your plants and drop into some soapy water, or feed them to your chickens. Because they blend in with foliage so well, you may want to do a little night hunting. Hornworms will glow in UV (black) light, so going out after dark and shining a black light on your plants will help you more easily find the pests. Make it a fun activity for the kids.
There are some organic pesticides and insecticidal soaps that will also mitigate the hornworm, but their efficacy largely depends on the caterpillars coming in direct contact with the product and should be used as a last resort.
If you grow roses or zinnias, you may have been plagued by Japanese beetles. They will also attack beans, grapes, raspberries, and fruit trees. These copper-colored beetles begin as white c-shaped larvae in your soil and have an adult life cycle of about 40 days. Their adult form becomes most prevalent in late-May or early June. The larvae will feed on the roots of plants, so if you notice brown patches in your lawn, it might be a sign of future Japanese beetles.
How to Deal with Japanese Beetles
Preventing Japanese beetles can be challenging. You can start by attempting to eliminate the grubs in the late spring and fall (beetles have 2 life cycles per year). Spraying a mixture of 2 tablespoons of liquid dishwashing soap with 1 gallon of water per 1000 square feet of lawn will cause beetle grubs to rise to the surface, where they will hopefully be removed by natural predators like birds. There are other lawn treatments like milky spore and parasitic nematodes that can be applied, but they can be expensive and time intensive.
Row covers or other coverings on your plants can help prevent the beetles from feeding. These are best used during their primary feeding period. It runs for about 8 weeks, beginning in mid to late May in the South and mid to late June in the North. During this period, you may also want to protect your roses by removing buds and only allowing them to bloom after the danger has passed.
One of the easiest and most attractive ways to prevent Japanese beetle infestation is to plant geraniums near the plants you most want to protect. Geraniums are highly attractive to beetles and contain a substance that will paralyze the beetles. You can then collect the beetles or hope some birds do the job for you.
When you see leaves that look like lace or just a skeletonized shape of a leaf, then you probably have a Japanese beetle infestation. Once you discover the infestation there are many different ways you can try to mitigate the situation.
Hand-picking the beetles might be time-consuming, but it is an effective way to remove them. Just knock them off into a water solution with some liquid dishwashing soap and they will drown.
Neem Oil spray is an organic method of deterring adult beetles from feeding. Neem oil will not kill adults, but it will cause the larvae they produce to die before maturity. Keep in mind that Neem oil is harmful to fish and other aquatic life, so don’t use it near ponds or lakes.
You can make a simple homemade insecticide with 1 teaspoon of dishwashing liquid and 1 cup of vegetable oil that is mixed well and then added to 1 quart of water. Top that off with 1 cup of rubbing alcohol and shake to emulsify. Add this to a spray bottle and spray on pests in 10-day intervals. Be sure to test it on a small area of your plants first to make sure there are no adverse reactions.
Japanese beetle traps with some sort of pheromone attractant are very effective. Just be sure to place them away from the plants you want to protect. You can also make an attractive trap using some rancid fruit cocktail placed in a bucket. Fill the bucket with water just up to the top of the fruit cocktail can to form a moat around it. Place the trap about 25 feet away from the plants you want to protect. The beetles will be attracted to the strong smell of fruit and drown in the water.
Growing a successful garden takes time, patience, and vigilance. Insect pests like beetles and caterpillars can cause a lot of damage very quickly. With some planning and careful monitoring, you should be able to keep your garden safe. Hopefully, we’ve provided some useful information that will help you keep your garden healthy and produce a bountiful harvest.