Introduction and Distribution:
Spodoptera littoralis, also known as the African Cotton Leafworm, Egyptian Cotton Leafworm or the Mediterranean Brocade, is native to Africa and Israel and widely found in both Africa and the Mediterranean Europe. It has been recorded several times in the UK, and even though it has been intercepted at U.S. ports, it is not known to be established in North America. It is considered a pest of national concern and may result in quarantine and/or regulatory actions if detected. It is a pest on vegetables, fruits, flowers and other crops. The establishment of Egyptian cottonworm in the continental U.S. would have the potential to negatively impact trade.
This pest has a very wide host range; it feed on over 40 plant families. Among their host are: okra, onion, pigweed, peanut, cabbage, cauliflower, pepper, citrus, taro, tea, cucurbits, carrot, fig, geranium, soybean, cotton, sunflower, tomato, lettuce, apple, alfalfa, tobacco, avocado, pine, pea, poplar, plum, pear, oak, potato, eggplant, spinach, clover, wheat, and corn.
Identification Characteristics and Life History Information:
Eggs are whitish-yellow and are laid in masses on the lower surfaces of young leaves. They are covered with hair scales from the female’s abdomen.
Six larval instars occur. Feeding damage is similar to S. litura, with initial larval feeding resulting in leaf skeletonization. Larvae are hairless and blackish-grey to dark green when recently hatched, as they mature they become reddish-brown or whitish-yellow. Caterpillars have dark and light longitudinal bands and two dark, semi-circular spots on their back. When recently hatched, larvae begin feeding on the underside of leaves, but as they mature they move towards the upper surface of leaves. Larvae may also feed on fruits, pods, and stems of plants. They can grow up to 1½ to 1 ¾ inches (3.81 to 4.45 cm) in length. They pupate ½ inches below the surface of the soil in a clay cocoon. When the pupae form, they are green with a reddish abdomen but they turn dark reddish-brown pretty quickly.
Adults are gray-brown and marked by grey to reddish-brown forewings with paler lines along the veins. The tip of the forewing (apex) is light brown, with a distinct white marking shaped like an “A” and a white, three-branched fork-like pattern. Hind wings are whitish, glossy with grayish-brown margins and veins as well as fringe hairs.
Confirming and Identification?
An entomologist will probably need to dissect the male genitalia of an adult moth to confirm identification. Field specimens may be confused with another exotic species of concern, Spodoptera litura, or other Spodoptera species currently occurring in the continental U.S., including southern armyworm (S. eridania), beet armyworm (S. exigua) fall armyworm (S. frugiperda), S. latifascia, yellow-striped armyworm (S. ornithogalli), S. albula, S. androgea, S. dolichos, S. pulchella, and western yellowstriped armyworm (S. praefica) . Initial screening questions can be directed to your local cooperative extension service county office http://www.csrees.usda.gov/Extension/ or your state-based NPDN lab. Go to the ‘Diagnostic Lab’ section of the NPDN website http://www.npdn.org/ and click on your home state. As with most moths, adults are nocturnal and often commonly begin a couple of hours before midnight. Researchers and survey specialists with the USDA-ARS, USDA-APHIS-PPQ, your local state department of agriculture, or your state-based university system may be currently surveying or researching survey methods for trapping Egyptian cottonworm with pheromone-based traps. For questions regarding survey programs in your area, contact your local Cooperative Agriculture Pest Survey Program. You can link to more information about this program on the National Agriculture Pest Information System website at: http://pest.ceris.purdue.edu/index.php.
Potential Economic Impact and Description of Damage:
If this pest were to be introduced and established in the United States, both the climate and hosts would be suitable for it to establish in approximately 49% of the country, resulting in severe economic and environmental impact. It is considered one of the most destructive agricultural pests within the subtropical and tropical range. Subsequently, the establishment of Egyptian cottonworm in the continental U.S. would also have the potential to negatively impact international trade. Due to its wide host range, it can attack several economically important crops all year round. It has shown to lower cotton yields by as much as 75%.
Regulatory Status and Management Issues:
Extension specialists or others that strongly suspect they have detected Egyptian cottonworm should contact their local state department of agriculture http://nationalplantboard.org/member/index.html . State and federal (USDA-APHIS-PPQ) regulatory officials may begin quarantine and eradication procedures if a confirmed population is detected. As Egyptian cottonworm has not established in the continental U.S., local management programs are not available. Remember that any attempt to manage this pest will only occur after regulatory officials have determined that eradication is not possible. The use of Bacillus thuringiensis (BT) has been suggested as a possible biological control option for this pest. For general information on Spodoptera literature, natural enemies, etc. please visit: http://www.aphis.usda.gov/import_export/plants/manuals/emergency/downloads/nprg_spodoptera.pdf
- Capinera, J.L. 1999. Fall armyworm Spodoptera frugiperda (J.E. Smith) (Insecta: Lepidoptera: Noctuidae). Found at: http://entnem.ufl.edu/creatures/field/fall_armyworm.htm
- Capinera, J.L. 1999. Beet armyworm Spodoptera exigua (Hübner) (Insecta: Lepidoptera: Noctuidae). Found at: http://entnem.ufl.edu/creatures/veg/leaf/beet_armyworm.htm
- Capinera, J.L. 1999. Southern armyworm Spodoptera eridania (Stoll) (Insecta: Lepidoptera: Noctuidae). Found at: http://entnem.ufl.edu/creatures/veg/leaf/southern_armyworm.htm
- Capinera, J. L. 2001. Yellowstriped armyworm Spodoptera ornithogalli (Guenée) (Insecta: Lepidoptera: Noctuidae). Found at: http://entnem.ufl.edu/creatures/veg/leaf/yellowstriped_armyworm.htm
- Forestry Images. Egyptian Cottonworm. Found at: http://www.forestryimages.org/browse/subimages.cfm?SUB=5010
- Meagher, R.L., J. Brambila, and E. Hung. 2008. Monitoring for Exotic Spodoptera species (Lepidoptera: Noctuidae) in Florida. Florida Entomologist. 91(4): 517-522. Found at: http://www.fcla.edu/FlaEnt/fe91p517a.pdf
- Pest Tracker. Spodoptera littoralis Useful Characteristics to Recognize this Target. Found at: http://pest.ceris.purdue.edu/searchpest.php?selectName=ITBCFPA
- USDA-APHIS. 2005. New Pest Response Guidelines Spodoptera. Found at: http://www.aphis.usda.gov/import_export/plants/manuals/emergency/downloads/nprg_spodoptera.pdf
- USDA. Spodoptera littoralis. Found at: http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?entqr=0&sort=date%3AD%3AL%3Ad1&ie=UTF-8&mode=simple&q=spodoptera+littoralis&num=10&ud=1&oe=UTF-8&navid=SEARCH&start=0
- Venette R.C., E.E. Davis, J. Zaspel, H. Heisler, and M. Larson. 2003. Mini Risk Assessment: Egyptian cotton leafworm, Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae). Found at: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/pra/slittoralispra.pdf