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Croci or Cabbagehead Caterpillar (CHC)

Common Name | Scientific Name | Geographic Distribution | Recognition and Diagnosis | Host | Biology and Ecology | Damage and Importance
Management Strategies


Common Name:

English: Croci, Cabbagehead Caterpillar (CHC), Larger Cabbage Webworm
Spanish: Croci, Gusano de la Cabeza del Repollo (GCR), Gusano Tejedor Grande del Repollo

Scientific Name:

Crocidolomia binotalis [Zeller] (Lepidoptera: Pyralidae)

Geographic Distribution:

Highland tropics of the Old World. Principally: Australia (Queensland), India, Indonesia, Taiwan, Thailand, Malagasy Republic, Mauritius, Philippines, South Africa. Croci has only been found in tropical and subtropical regions.

Recognition and Diagnosis:


  1. Size: From 18 to 25 mm long when fully grown.
  2. Color:Croci have dark heads and appear grey at hatching and light green thereafter, depending largely on the color of the leaves they are consuming. They are easily recognized by their distinctive yellowish white stripes: three dorsal and two lateral. These stripes disappear only when larvae are close to pupation.
  3. Location: Neonate larvae are gregarious on the underside of leaves and initially create a small window-like appearance by feeding without completely penetrating the leaf. As third instars, ~1 cm long, 4-5 days after hatching, they move towards the apical meristem of the plant or head. A ravaged plant center with mats of frass and silk or false cabbage head with no real head or several small heads are evidence of Croci damage.
  4. Behavior: For the first 4 or 5 days from hatching, the small larvae feed on the underside of the leaf without eating through the uppermost leaf layer, creating window-like damage in the leaves. After this they move to the growing point of the plant center or bore to the center of the head. In the open center, groups of Croci will conceal themselves beneath silk webbing and frass.

Pupa and Cocoon
  1. Size: 8.5 to 10.5 mm long and cylindrical in form.
  2. Color: Croci pupae are olive green and light brown turning darker coppery brown closer to eclosion. Larvae weave a loose cocoon which they cover with bits of available substrate, usually soil.
  3. Location: Larvae burrow into the soil near the base of the host plant to pupate.

Adult Moth

  1. Size: Male Croci are usually slightly larger and longer than females. The male wing span is 20-25 mm and body length 11-14 mm. Female wing span is 18-25 mm and length 8-11 mm.
  2. Color: In both males and females there is considerable variation in delineation of beige markings on the cream background of the forewings. Males, in general, display great delineation and can be recognized by a dark tuft of hairs on the anterior margin of each forewing which the females lack.
  3. Location: During the day they rest in the shade and can be stirred by hedgerow and crop plant canopies.
  4. Behavior: Croci are active in the twilight, night, and dawn hours. Adult females can live as long as 30 days and lay as many as 10 or more egg clusters for an average total of 350 eggs.


  1. Size:
  2. Eggs are laid in overlapping or "shingled" masses of ~10-300 eggs. A large egg mass will measure 5 mm in diameter.
  3. Color: Egg masses are light green in color and are easily camouflaged on host plant leaves.
  4. Location: Egg masses are usually laid on the underside near the base of leaves.


Croci larvae feed on wild and cultivated crucifer plants. While they are capable of surviving on any part of these plants, they demonstrate attraction to particular plant parts such as growing centers, blossoms and pods.

Biology and Ecology:

Croci life cycle is completed in approximately 28 days, depending on temperature and humidity. They are almost exclusively found in hot humid highland tropics, and constitute a more serious pest problem during the dry season since heavy rains can drown small larvae. Egg incubation takes 4 days. Larvae reach third instar in 4 to 5 days at which time they begin boring into cabbage centers or movement towards the plant parts of their choice. The remainder of their larval development takes approximately 12 more days, during which time they feed ravenously. Adult females can live as long as 30 days and lay as many as 10 or more egg clusters for an average total of 350 eggs. On cabbage crops oviposition peaks occur 35-40 after transplanting and again 30 days later.

Damage and Importance:

Until the advent of synthetic insecticides Croci was considered the foremost pest of crucifers in the Old World. Even a single larva will destroy an entire plant by feeding on its growing center. Larvae are extremely mobile and can easily travel 2 or more meters to reach a preferred host plant. Also, as soon as larvae have begun boring into a cabbage head they are protected from contact with insecticides. In the Old World, Croci is a devastating pest of cabbage, particularly where efforts are made to reduce dependence on bi-weekly pesticide applications.


Management Strategies:

Sampling and economic thresholds:
For approximately the first 70 days from cabbage planting (or 40 days from transplant) monitoring for Croci damage is quick, effective, and essential for determining appropriate pest management action. After this time, when the cabbage plant is larger and structurally complex it becomes too difficult to detect Croci and sampling becomes much less effective.
Where to sample:
During the first 40 days from transplant, Croci can be effectively monitored by looking for the window-like leaf damage created by the early larval instars. This must be carried out twice weekly in order to detect the larvae before they move towards the growing center of the plant.
Economic threshold:
During the first 40 days after transplant, Croci can be monitored and groups of young larvae can be killed by hand or spot-sprayed with products based on Bacillus thuringiensis (Bt). This method is time efficient while Croci densities remain below 15%. If the percentage of plants infested with Croci exceeds 15% it becomes more efficient to spray the entire field.
After the first 40 days from transplant, monitoring is no longer sufficiently effective. Cabbage must be sprayed routinely twice each week.
Biological Control:
Several Hymenopteran larval parasitoids have been identified for Croci, but none has demonstrated greater than a 7% parasitization rate. The first egg parasitoids were discovered in 1995, but these two species of Trichogramma have not yet been identified.
Current IPM Practices:
Planting season
It is preferable to plant cabbage during the rainy season when Croci populations are reduced.
Hand removal of egg masses and early instars
Success in locating egg masses and larval groups entirely depends on plant architecture. During the first 40 days after cabbage transplant, while leaves are still open and relatively few, the window-like patches created by the gregarious early Croci instars are easily detected and squashed. During this time it takes one person less than 3 hours per 2000 plants to monitor and remove larval groups by hand. This can be done twice each week, as larvae will not have dispersed from their aggregation within the time between monitoring. For some farmers the time necessary to do this during the first 28 days may be more than seems worthwhile given the usually low (~3%) Croci densities. They may prefer to monitor against a surprisingly high infestation only once each week.
By 40 days after transplant the time required for hand monitoring increases significantly and accuracy of detection decreases dramatically. Even with meticulous efforts at least 20% of a cabbage crop can be ruined by Croci.
Spot spraying
Twice weekly spot spraying of Bt on only those cabbage plants with visible Croci is an effective means of control until 40 days after transplant and until pest densities reach 15%. Backpack sprayers that deliver a fine mist must be used since coverage with hand held spray bottles is not adequate.
After 40 days after transplant, monitoring and spot-spraying are no longer effective since Croci become too difficult to to detect. It is best to spray twice weekly with Bt.
Trap Cropping
Some trap cropping experiments have proved very successful. In India 15 rows of cabbage were successfully intercropped with Indian Mustard (planted 12 days prior and 25 days post cabbage transplant).
Chemical strategies:
Pesticide recommendations and consideration of resistance
Croci has not demonstrated resistance to any of the insecticides employed for its management. The focus of the problem is assuring contact with larvae before they begin boring into the cabbagehead center where they are inaccessible. This leads to bi-weekly spray programs. While this strategy very effectively manages Croci, it cannot be considered isolated from the Diamondback moth pest complex of which it is part. Bi-weekly spray programs easily encourage evolution of pesticide [even Bt] resistance in DBM. In addition, in many highland areas of Asia, Diadegma semiclausem [Hymenoptera: Chalcididae], a larval parasitoid, has proven to provide very effective control of Diamondback moth. Spraying against Croci decimates the D. semiclausem population.
Spray techniques
Use of spreader stickers is recommended to increase spray coverage on the waxy surface of cabbage leaves. Croci early instars will be found on the underside of leaves so it is important to spray the underside of leaf surfaces thoroughly. Hydraulic nozzles and those producing fine spray mist provide the best coverage.


Othman, N. 1982. Biology of Crocidolomia binotalis [Zeller] (Lepidoptera: Pyralidae) and its Parasites from Cipanas Area (West Java). PhD thesis BIOTROP. SEAMEO Regional Center for Tropical Biology, Bogor, Indonesia.
Schellhorn, N. 1995. pers. comm. from Seribu-dolok, North Sumatra.
Schellhorn, N. 1995. Farmer Trainer's group experiment and control strategy for a cabbage pest Crocidolomia binotalis [Lepidoptera: Pyralidae], in the highlands of North Sumatra.
Srinivasan, K. and Krishna Moorthy, P. N. 1991. Indian Mustard as a trap crop for management of major lepidopterous pests on cabbage. Tropical Pest Management 37(1), 26-32.


Technical content
Nancy Schellhorn, Nooraini Othman, and Rebecca Smyth
Cathy Weeden, Alfredo Rueda, Tony Shelton, and Linda McCandless
Rebecca Smyth

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