Vigilance is your best weapon in the fight against cauliflower pests. If you see discoloration, wilting, holes in the leaves, damage to stems or roots, or insect infestation or eggs, take immediate action. Pests can reduce leaves to skeletons and then burrow into heads, while others attack at root level. And pests are a primary source of disease spread.
Here are some of the pests you may encounter:
The aphid is a tiny, sap-sucking critter that eats through leaves and flower heads. It spreads plant diseases and leaves a trail of honeydew that attracts other insects and promotes the growth of fungus. Look for eggs on the underside of leaves and tell-tale clumps of stacked-up aphids, or misshapen, curling, stunted, or yellowing leaves.
Rinse aphids away with a stream of water. You can also use neem oil to kill them, or dust plants with flour. You can also try spraying leaves with a mild soap solution in water, reapplying every two to three days for two weeks.
Prevent aphids with beneficial insects such as ladybugs, lacewings, or parasitic wasps. You can order these online and they’ll keep aphids controlled from the start.
Also try companion planting to keep aphids away. They’re repelled by catnip, and are attracted to mustard and nasturtium.
This is a leafeater that can chew a crop to bits before you know it. It’s a green caterpillar with an inchworm-like movement and a white stripe. Adults are brown moths with a silver figure-eight on the wings. Eggs are laid on the undersides of leaves and are domed and ridged.
Treat cabbage loopers with Bacillus thuringiensis, or douse plants with regular white flour (not self-rising). Dew on the flour will lead to petrified bugs that you can rinse off the following day.
This moth with a white diamond on its folded brown wings has a larva that’s as voracious a feeder as the adult moth is. When you see a moth, look for eggs underneath the leaves.
Unfortunately, the cabbage moth has developed a resistance to some pesticides. Try BT or neem oil, but a better bet is parasitic wasps. Again, companion planting, in this case collard greens, can lure the critters away from your cauliflower crop.
Cabbage Root Fly/Maggots
Maggots are the larva that turn into cabbage root flies. They’re tough to control because they hatch and feed underneath the soil, so you may only know they’re there by the appearance of stunted growth or wilted foliage. They’re more common in northern climates.
Like most maggots, these critters group together in clumps of white, legless maggots about 1/3 of an inch long. They feed voraciously on root systems of cole crops. The cabbage root fly resembles a small house fly, and also feeds on plants for about 10 days before laying eggs at the base of plants. You might spot eggs laid in rows at the base of plants.
Plants attacked by flies and maggots inevitably die. But if you see flies around your plants, look for eggs in the soil and destroy them. Try applying diatomaceous earth (DE) on the ground to discourage egg laying. Dig down to examine the roots of plants showing distress and discard victims.
You can also try live beneficial nematodes that you can buy online to attack soil-borne pests. Alternately, try installing “cabbage collars” of cardboard around the base of the plant to prevent egg laying. Then there are sticky traps for the flies, and you can plant radish as a trap for the maggots. Finally, you might be able to dig up your plants, swish the roots in cold water and allow the maggots to drown, then replant your cauliflower.
Practice crop rotation to avoid overwintering pupae, and till the garden in fall and spring to expose the pupae.
Cabbage White Butterfly
The cabbage white butterfly lays eggs that become hungry larvae. They’re also known as cabbage worms or imported cabbage worms, and they devour leaves and bore into lower heads, ruining a crop.
The larva are velvety green worms with a few yellow stripes. They emerge from the butterfly’s eggs laid underneath leaves. Hand-pick the eggs if possible, or spray with BT every one to two weeks. Wash off any remaining pests after harvest with water and a small amount of detergent.
This is a tiny white fly with scaly nymphs that infest the undersides of leaves, feeding on leaf sap and excreting honeydew, which promotes sooty mold growth. Many growers simply put up with this pest because while it disfigures a plant’s leaves, it doesn’t damage the heads.
There are two types of flea beetle, the crucifer flea beetle and the striped flea beetle. They have extra-large hind legs that allow them to jump like a flea. These insects chew holes in the leaves that don’t go all the way through the leaves.
There is no organic product to fight flea beetles, so try a pyrethrum spray, use row covers as protection, or try to time planting to avoid their peak feeding time in early summer. You can also try trap cropping using mustard as a first line of defense.
How do you fight off cauliflower invaders? Please share your methods with us in the comments below.