QUESTION: Are there worms in cauliflower? How should I be checking my plants? – Tracy R.
ANSWER: Unfortunately, a range of worms can spoil your cauliflower crops before it even starts to develop crowns for you to harvest. Cauliflower is a cool weather crop which requires a minimum of four long months between sowing seeds and harvesting, so it is very important to keep a close eye on each of your cauliflower plants, especially when they are young, looking for worms that can damage your crops above and below the soil’s surface.
The most common worms that you are likely to find on your cauliflower plants are cabbage loopers, armyworms, and cabbage worms, all three of which attack the plant above the ground, as well as cabbage maggots, which attack the plant from below the surface of the soil.
Above the ground, look for small green worms that are about one inch long. Loopers, also called inchworms, are green with white stripes and arch their bodies as they move. They feed on the leaves of cauliflower plants during the night and hide beneath the leaves during the day.
Cabbage worms are green and hairy, with faint yellow-orange stripes. Armyworms get their name from their appearance, which is similar to camoflauge, with primarily green bodies and mottled brown splotch-like markings. Both cabbage worms and armyworms feed on the leaves as well, but armyworms attack them in small groups, taking out large patches of foliage overnight.
Below-ground, cabbage maggots are white, with a pointed front and flat end, each approximately one-third of an inch long. Cabbage maggots burrow their way through cauliflower roots, eating their way from the roots to the base of the plant.
The above-ground worms are tough to spot, as they are the same color as the leaves they hide beneath. All three types leave behind irregular shaped holes in the foliage and can easily kill young seedlings. Unfortunately, maggot damage is only recognizable once the plants stop growing and die, and there are no treatments available to keep them from killing your plants.
Above-ground worms can be dealt with in two ways. They can be picked off by hand and destroyed, which is the most effective method. Alternatively, you can treat the plants as soon as you see signs of damage or spot the culprits by spraying BT, or Bacillus thuringiensis, a bacterial herbicide. Unfortunately, BT is only effective against young caterpillars and will have little to no effect on adult worms.