February 2025
Cabbage Looper by Wizzie Brown
Cabbage loopers are caterpillars that can be found on multiple crops such as tomatoes, squash, pumpkin, melons, cucumbers, greens, beans, peas, celery, cabbage, lettuce, broccoli, and cauliflower. They tend to have sporadic populations, with heavy infestations one year and light the next.
Loopers have a complete life cycle with four life stages: egg, larva, pupa, adult. Eggs are dome shaped and laid singly or in small clusters on both tops and bottoms of foliage. Eggs are yellow to green in color. Larvae change colors as they get older, beginning a whitish color with hairs and turning greenish with a white stripe down the side of the body and losing hairs as they age. Larvae have three pairs of true legs- these are on the thorax which is directly behind the head- and three pairs of prolegs, which are also known as “false legs”. Prolegs are fleshy protuberances on the abdomen that help the loopers to walk and cause their “inching” movement where they scrunch up the body and then stretch it out to move forward. Mature larvae can reach lengths of 1.25-1.5 inches. Pupae are white, thin and on the underside of foliage or in debris in the soil. Pupal cases are around 0.75 inches, look like a silken mat, and start off green but turn brown. Adults have a wingspan of 1.25 inches and mottled brown and gray in color. The center of the front wing has a light dot and U-shape. Adults are typically active at night.
Damage is caused by the larvae feeding on foliage with their chewing mouthparts. Smaller larval stages feed on the underside of leaves and tend to feed more on tender parts of the plant while larger stages chew large holes in leaves and can bore into heads of cabbage. When looking for cabbage loopers, you may not see the caterpillars, but may instead find their frass which look like small brown pellets.
Management strategies could include row cover before plants are infested, egg removal, insecticidal soap on smaller stages, Bacillus thuringiensis variety kurstaki, spinosad, or neem/ azadirachtin. As with any IPM program, try to conserve beneficials by using pesticides as a last resort.
For more information or help with identification, contact Wizzie Brown, Texas A&M AgriLife Extension Service Program Specialist at ebrown@ag.tamu.edu.
This work is supported by the USDA-NIFA Extension Implementation Program, project award no. 2024-70006-43508, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Texas AgriLife Extension Service or the Texas AgriLife Research is implied. Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability, or national origin.
*********************************
January 2025
Insect Life Cycles by Wizzie Brown
Insect life cycles can be broken down into two major categories: incomplete and complete. Incomplete can then be further broken into three varying types.
Incomplete metamorphosis, also called paurometabolous, has three life stages. The first stage is the egg which hatches into an immature insect called a nymph. The nymph eats, grows and molts, going through several different nymphal stages called instars. With each successive molt, the nymph grows larger and begins to develop wings. Nymphs look similar to adults in appearance with the exception that they do not have fully developed wings. The final stage is the adult which has fully developed wings (of course, unless the insect is wingless i.e. bed bugs). Adult insects seek out the opposite sex, mate, and females lay eggs to begin the cycle anew. An example of an insect with paurometabolous metamorphosis is a cockroach.
One variation of incomplete metamorphosis is called ametabolous and happens in primitive insect groups. This type of metamorphosis also has three life stages: egg, nymph, and adult, but the immatures/ nymphs look exactly like the adults except they are smaller in size. Dissection may be needed to tell immatures from adults. An example of an insect with ametabolous metamorphosis is a silverfish.
The second variation of incomplete metamorphosis is called hemimetabolous and insects with this type of metamorphosis have an immature stage that is aquatic. Again, there are three life stages: egg, nymph, and adult. The nymphal stage of hemimetabolous insects lives in water and is called a naiad. The last nymphal instar- or the last stage before the insect molts into an adult- crawls out of the water onto a dry surface so the adult insect can emerge without getting their wings wet. An example of an insect with hemimetabolous metamorphosis is a dragonfly.
A dragonfly is an example of a hemimetabolous metamorphosis
The second basic category of metamorphosis is called complete, or holometabolous, metamorphosis. Complete metamorphosis has four life stages: egg, larva, pupa, and adult. Eggs are laid by fertilized adult females and hatch into the second stage called a larva. Larva* look very different from the adults and often feed on different food sources than adults. Larva are often have elongated bodies, no wings, and may or may not have legs. After going through several instars, or larval stages, the insect turns from a larva into a pupa. The pupa is a transformation stage for the insect where it rearranges it’s body into the adult form. Sometimes you can see adult features in the pupal stage, but other times the pupa is within a case- like with fly or butterfly** pupa- and you cannot see development. The adult insect emerges from the pupal stage, seeks out a mate for mating, and continues the cycle.
*Larva is the general name for immature insects that go through complete metamorphosis. There are more specific names for various types of larva based on what Order they belong to. Larva that are in the Order Lepidoptera and turn into butterflies and moths are referred to as caterpillars while larva in the Order Diptera and turn into flies are called maggots. Also in the Order Diptera, wigglers are the larval stage of mosquitoes (and mosquito pupae are often called tumblers). Larva that turn into beetles, Order Coleoptera, are called grubworms or wireworms (depending upon what type of beetle they turn into).
**A butterfly pupal case is called a chrysalis.
For more information or help with identification, contact Wizzie Brown, Texas AgriLife Extension Service Program Specialist at 512.854.9600.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Texas A&M AgriLife Extension Service or the Texas A&M AgriLife Research is implied.
The Texas A&M AgriLife Extension Service provides equal access in its programs, activities, education and employment, without regard to race, color, sex, religion, national origin, disability, age, genetic information, veteran status, sexual orientation or gender identity.