|Crop Knowledge Master|
Psycnodered quadrimaculatus (Guerin-Meneville)
Jayma L. Martin Kessing, Educational Specialist
Ronald F.L. Mau, Extention Entomologist
Department of Entomology
Host plants include cabbage, cucumber, dishcloth gourd, garden bean, green bean, lettuce, lima bean, luffa (angled and smooth), mustard cabbage (kai choi), okra, pole bean, pumpkin, spiny cucumber, squash, sweet potato, and white mustard cabbage (Zimmerman, 1948). An alternative weed host is Portulaca or pig weed.
The bean mirid is a neotropical species described from Cuba and it is found from Mexico, as far north as New Hampshire, and west to Southern California (Fullaway & Krauss, 1945). It is also present in the West Indies. This bug was first reported on Oahu in 1929 and is now present on Kauai, Hawaii, Maui, and Molokai as well.
This insect feeds with piercing-sucking mouthparts. Injury consists of the destruction of the leaf and stem surface causing a scarification of white stippling on a green surface (Fullaway & Krauss, 1945). Bugs can become abundant on bean foliage. Foliage becomes heavily spotted with black excrement on the underside of leaves, and lightly speckled on the upper surfaces (Zimmerman, 1948).
The flask shaped eggs are small and translucent. They are inserted into stems and the larger leaf veins. Eggs hatch in a few days.
Nymphs are small, greenish white and wingless with the same basic body shape of the adults. During the approximately 2 week nymphal period they molt 5 times and continuously feed.
The bean caspid is long, black-mottled gray and white with white wing tips and pale legs and antennae. They measure about 1/8 inch in length (Fullaway & Krauss, 1945). See Blatchley (1926) for a detailed description of the adult.
The bean caspid is attracted to lights and hops freely.
Several natural enemies are present in Hawaii that give some control of the bean caspid. The parasitic wasp Anagrus yawi Fullaway was introduced from Mexico in 1943 and exhibits some control. This bug is also controlled by the fungus, Entomophthora sphaerosperma Fresenius. The reduviid bug, Zelus renardii preys on the bean caspid. These natural enemies considerably reduce bean caspid numbers and consequently, bean caspid damage to crops.
Chemical control is rarely necessary.
Blatchley, W. S. 1926. Pycnoderes quadriculatus Guerin. pp. 869. In: Heteroptera or True Bugs of Eastern North America. The Nature Publishing Company: Indianapolis. 1116 pages.
Fullaway, D. T. and N. H. L. Krauss. 1945. 72. Pycnoderes quadriculatus Guerin. In: Common Insects of Hawaii. Tongg Publishing Company, Honolulu, Hawaii. 228 pages.
Zimmerman, E. C. 1948. Pycnoderes quadriculatus Guerin-Meneville. pp. 191-192. In: Insects of Hawaii. A Manual of the Insects of the Hawaiian Islands, including an Enumeration of the Species and the Notes on their origin, Distribution, Hosts, Parasites, etc. Volume 3. Heteroptera: Miridae. University of Hawaii Press, Honolulu. 255 pages.
MAR/1992 revised JUN/1992.