Striped and spotted cucumber beetles favor cucumbers and melon vines. These insects spread bacterial wilt from plant to plant, a disease that is often fatal. When striped cucumber beetles are a chronic problem, the best course of action is to choose bacterial-wilt-resistant cucumber varieties.

Image: Alexandria Szakacs

As the name implies, the surest way to attract Colorado potato beetles to your garden is by planting potatoes. These insects lay clusters of orange-yellow eggs on the undersides of leaves, which hatch into highly destructive orange larvae that feed voraciously and grow quickly. While beetles can be killed at any stage, it's easiest to remove the adults and eggs by hand.

Image: Олександр К

Eggplant flea beetles can destroy an eggplant plant in just a few days. While many insecticides can kill these pests, the most effective method requires protecting plants with summer-weight floating row covers. These covers transmit enough sunlight while physically blocking the beetles from the plants.

Image: Weronika Romanowska

These insects might look striking, but they are the worst enemy of summer kale, broccoli, and other brassicas. They suck the sap from leaves, leaving behind unsightly pockmarks.

Harlequin cabbage bugs can be picked off by hand, and wearing a face mask can help you avoid the unpleasant odor they emit. Also, spraying them off with a jet of water will help knock them back.

Image: David Clode

In a similar case to the one we mentioned earlier, it’s the larvae of Mexican bean beetles that cause the most damage. The adults emerge in late spring but usually don’t become a serious problem on bean plants until midsummer.

The best way to deal with this pest may seem harsh, but necessary if you want to keep your other plants safe: you must completely harvest and remove the infested plants from the garden. After picking all the beans, the entire plant should be pulled, bagged, and taken far away from the garden.

Image: Viktor Talashuk

Tiny red spider mites live on the undersides of leaves, where they feed on plant sap. To control them, the best approach is to increase humidity and, if growing under glass, introduce a biological control. Alternatively, organic sprays can also be effective.

Image: adege

These moths are responsible for the maggots found in apples. To avoid these, spray emerging caterpillars twice with bifenthrin, starting in midsummer. Another useful method involves hanging pheromone traps in late spring to catch male moths and prevent them from mating.

Image: Mikkel Frimer-Rasmussen

Winter moth caterpillars hide inside webbed leaves on fruit trees during the spring. One effective way to control these pests is by applying sticky traps to capture the adult moths before they lay eggs.

Image: Erik Karits

Scale insects cluster on branches and beneath leaves, often leading to poor plant growth. Other common symptoms include sticky excretions (called honeydew) and the development of sooty mold, especially on evergreens. The solution is to wash off the mold and spray the plant with horticultural oil.

Image: efraimstochter

The Viburnum beetle and its larvae can create holes in the leaves. The answer to this is to spray the areas affected during the spring with bifenthrin or thiacloprid.

Image: Grant Ofstedahl

The adult weevil is a nocturnal, flightless insect that makes notches in the leaves of your plants. To control this pest, apply nematodes by mixing them with water and applying the solution to the soil in the affected area.

Image: Henry Lai

The rose slug is easy to overlook until its feeding starts to damage the leaves. Rose slugs feed on the undersides of leaves, out of sight, nibbling on the tissue between the veins. By the time they’re done, the leaves often resemble skeletons.

Luckily, the solution only requires blasting the slugs off the roses with a spray of water or treating them with spinosad, a bioinsecticide derived from soil bacteria.

Image: Naoki Suzuki