Question: I have holes in my spinach leaves. What eats the spinach in the garden? Is there anything I can do to prevent pest damage? -Trent W.
Answer: Spinach and other leafy greens in the garden can attract a variety of insects and pests, which will chomp on the leaves you’re growing for your own meals. Below we’ve listed the pests that could be munching on your homegrown spinach as well as ways to protect your garden from them.
- Beet armyworm: These caterpillars with their distinctive dark pattern can wreak havoc in the spinach patch. Like with other caterpillars, a treatment of botanical Bt (Bacillus thuringiensis) is an effective and natural way to fight the pests off and prevent them from returning. You’ll dilute two to four teaspoons of botanical Bt per gallon of water you use, and spray the treatment onto the upper and lower leaves of your spinach.
- Cabbage loopers: Cabbage loopers will consume spinach so voraciously, your plants may be left without leaves, or with only the veins/skeleton of the leaves remaining. These pests can be identified visually as green caterpillars that transform into white moths, and they move with a characteristic “looping” motion that looks a lot like an inchworm’s walk. Botanical Bt (Bacillus thuringiensis) is a safe, natural treatment to fight cabbage loopers along with other types of caterpillars. Dilute two to four teaspoons of the botanical Bt in each gallon of water needed to cover the affected area, then spray the mixture over the upper and lower leaves of your spinach plants.
- Leafminers: This larval form of several insects that grow into flies, beetles, and moths got their name for the “mines” they leave in leaves—pale squiggles between the surfaces of the leaves. The leafminer larva may be visible as a dark spot at the end of the pale trail they’ve eaten in the leaf. The quicker you act against leafminers the better, as plants that are hit hard by these pests may end up dying before you can save them. You can deploy wasps that feed on leafminer insects called Diglyphus isaea. If you don’t mind chemical treatments, you can also turn to azadirachtin growth-regulating insecticide. Use half a teaspoon per gallon of water. You’ll need one to two gallons of the azadirachtin treatment for every 1,000 square feet of garden you need to treat.