Creeping inside your garden or commercial vegetable field are certain pests that would rather feed until they reach two to three sizes larger. Young and small celery plants appeal to them. They don’t care that the grower wants to market his produce blemish free and that the grower intends on profiting from his hard work, either by consuming celery or selling at farmers markets or other venues.
Some insects are important for the celery grower to recognize: aphids, leafminers, beet armyworms and cutworms. These pests can damage the celery plant due to their feeding. Let’s take a closer look.
The aphid is so small that a grower almost needs a magnifying glass to see it clearly. It can range from 0.04 to 0.08 inches long, according to information from Susan Webb, an entomologist with the University of Florida. The pear-shaped green peach aphid is colored green to yellow to almost pink. The adults with wings sport a black spot over their abdomen. Small nymphs begin feeding almost immediately after birth and reproduce quickly. Within a few days, they reach adulthood.
When feeding, aphids have sucking mouthparts that they use to pierce plant tissue and suck out the plant’s juice, Webb said. While doing this feeding, aphids can inject toxins that lead to irregular growth of the celery plant. Besides injecting toxins, aphids can excrete sticky honeydew, which causes mold to grow.
Adult aphid populations can increase rapidly, and one of their most destructive negatives is that they can transmit more than 100 plant viruses, Webb said. Specifically, the green peach aphid also likes feeding on plants such as cabbage, parsley, turnip, lettuce, chard, endive, tomato, potato, pepper, beets, spinach and mustard greens. If they feed on all of these, the viruses spread to these plants, too. Besides spreading viruses, aphids can contaminate celery for the fresh market industry. They can leave honeydew and cast skins on the produce, thus reducing the crop’s market value.
A leafminer is a small adult insect that is less than 0.1 inches in length, Webb said. Their body is gray and black in color, their legs are yellow and their wings are transparent. They have a yellow-colored head with red eyes. Their eggs are oval-shaped and hatch into small maggots, which can feed on the leaf.
The female feeds by puncturing the plant leaf and sucking out the juice, according to Webb. Because it cannot puncture the leaf, the male feeds after the female. Their damage may or may not reduce celery yield. Research indicates the damage may not affect yield if it is not severe.
Quality is a different story. If celery is unattractive and unmarketable, graders may reduce their grade. Webb said that if growers protect their plants from damage in the last month of the growing season, they may avoid quality issues.
The serpentine leafminer, perhaps one of the most damaging insects, likes celery, parsley and many other vegetable crops.
3. Beet armyworm
The adult beet armyworm has dark-colored front wings, Webb said. It sports mottled, light-colored markings. Its hind wings have white scales. The females can lay more than 600 eggs underneath celery leaves. In three to four days, larvae emerge from egg masses. The caterpillars eat in groups. As they age, they separate and go out on their own. Once they’ve fed for several weeks on the petioles, they establish a cocoon. Adults emerge within one week or so. Besides celery, they like to feed on corn, pepper, tomato, potato, onion, pea, sunflower, citrus and soybean. Their feeding can cause undesirable crops of vegetables or fruit.
Beet armyworms can survive winters in Florida, Webb said, and can go through many generations within a year. In the Florida, beet armyworm populations are greater from late March through mid-June. However, they are present and smaller in number from mid-August through October.
Cutworms are a nuisance to celery growers. They can be a species of granulate or black. The moths feed on the plant’s nectar, then they drop eggs on field debris, stubble or celery leaves that are close to the ground, according to Webb. The wings of the granulate cutworm moth stretch 1.2 to 1.7 inches. Their front wings are yellowish-brown, and their back wings are white.
The eggs of the cutworm are white in color with a dark appearance. The black cutworm lays its eggs either as one or in a group of up to 30, Webb said, but the granulate cutworm lays its eggs either as one or in small clusters.
The larvae emerge in three to six days and are a gray to reddish-brown color, she said. Their abdominal area has a yellowish-colored mark. Along their bodies are a gray line and white or yellow spots. Growers will notice larvae as they curl up, if disturbed. Larvae like to stir about at night when they feed on celery leaves and stems. In the daytime, they retreat underneath the soil near the plant’s base. Eventually, larvae pupate, and adults emerge in 10 to 20 days.
Don’t let pests ruin your produce. Fight back by knowing which insects are present.