1008 C Collembola Department of Agriculture, Miscellaneous Publication No Colonization 1443, Washington, DC, 103 pp. Available Online at http:// www.sel.barc.usda.gov/Selhome/collpres/contents.htm The introduction and establishment of a species, usually a beneficial insect, in a new geographic Collembola area or habitat. An order of hexapods in the class Entognatha, and sometimes considered to be insects. They Colony commonly are called springtails. Springtails A group of individuals, other than a mated pair, which rears offspring in a cooperative manner, and may construct a nest. (contrast with aggregation) Colleterial Glands Female insects commonly secrete glue that Colony Fission attaches the egg to a substrate. Also secreted in some cases are jelly-like materials, oothecae, or pods Among social insects, the same as budding: multi- containing the individual eggs. The glands that plication of colonies by the departure from the secrete these are known by various names, including parental nest of one or more reproductive forms accessory, mucous, cement, and colleterial glands. accompanied by workers. Thus, the parental nest remains functional and new ones are founded. Colletidae Colony Odor A family of bees (order Hymenoptera, superfamily Apoidae). They commonly are known as plasterer The odor specific to a particular colony. This odor bees and yellow-faced bees. allows social insects to identify their nestmates Wasps, Ants, Bees and Sawflies among others of the same species. Bees Social Insect Pheromones Collophore Colorado Potato Beetle, A tube-like structure located ventrally on the first Leptinotarsa decemlineata (Say) abdominal segment of springtails (Collembola). (Coleoptera: Chrysomelidae) donaLd C. weBer Colobathristidae USDA Agricultural Research Service, Beltsville, MD, USA A family of bugs (order Hemiptera, suborder Pentamorpha). Colorado potato beetle is the most important Bugs insect pest of potatoes in the northern hemisphere. Larvae and adults feed on potato foliage, and Coloburiscidae under many agricultural conditions the pest will completely defoliate the crop if not controlled. It is A family of mayflies (order Ephemeroptera). also a major pest of eggplant (aubergine) and Mayflies tomato in some regions, as well as feeding on Colorado Potato Beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) C 1009 solanaceous weeds such as horsenettle, Solanum photoperiod, and availability and quality of host carolinense. Although it is occasionally found on plants. In the spring, overwintered adults emerge other nightshade crops such as peppers (Capsi- from the soil and begin their search for host plants cum), tobacco, and husk tomato (Physalis), it can- to feed upon. This commences with walking, but not complete its life-cycle on these hosts. after a few days beetles may take to flight. The -yel The original range of Colorado potato beetle low-orange eggs, laid on leaf undersides in masses was probably restricted to southwestern USA and/ of 20–60 (several hundred to a few thousand total or northern Mexico, where the host plants were per female), soon hatch into leaf-feeding larvae the spiny nightshade herbs Solanum rostratum which eat about 40 cm2 of foliage. The fourth instar (buffalobur) and Solanum elaeagnifolium (silver- larva drops to the ground and digs down a few cm leaf nightshade). The species was described in to pupate in the soil, emerging 10–20 days later as a 1824, but the first occurrence on potato was not callow adult. Also a voracious leaf feeder, the imago reported until 1859 in Nebraska. From there it consumes up to 10 cm2 per day. Depending on food, spread rapidly, especially eastward, reaching the photoperiod, and temperature, this young adult Atlantic coast of North America in 1874. By then may mate and reproduce, or after feeding, bury the potato crop was a staple food, and the spread itself 10–50 cm deep in the soil to spend months in of Colorado potato beetle infestation prompted diapause before emerging the next spring. early development of arsenical pesticides and In areas where tomatoes abound, it has application methods in the USA. evolved an improved fitness on this plant, as in the In 1870, responding in part to the threat of southeastern USA and Uzbekistan. Even where it Colorado potato beetle introduction, Germany does not thrive on tomato, large numbers may established the first-ever quarantine law followed damage this valuable crop. In contrast, potato within several years by other European countries. plants can tolerate light to moderate defoliation at Following the eradication of numerous isolated certain times of year, but without control, major to European introductions, its establishment into complete crop loss is common. A typical economic France in 1921 initiated another rapid geographic threshold is one adult equivalent per plant, where invasion which now includes all of Europe (except small larvae are counted as equivalent to 1/4 of for the United Kingdom, Ireland, and Scandina- one adult, and large larvae (3rd and 4th instars) via), continues through central Asia eastward into equate to 2/3 of an adult. Yield impact is depen- China, and threatens to spread into east and south dent on timing, variety, and other crop stresses. Asia, where one-third of the world’s potatoes are In early years, control relied on hand-picking, grown. The range is now about 8 million km2 in but this gave way to arsenical insecticides and in North America and a like area in Eurasia. Climati- the 1940s the more powerful synthetic chemical cally favorable areas not yet infested include east controls. No other agricultural pest better exempli- Asia, parts of south Asia temperate South America fies evolution of resistance to insecticides. Within and Africa, Australia and New Zealand. the first decade of DDT use, it was failing against Colorado potato beetle adults are approxi- Colorado potato beetle in the intensive potato- mately 10 mm long, convex, with cream-yellow and growing region of Long Island, New York, USA. black striped elytra, and variable black markings Resistance followed to numerous other chlorinated (Fig. 81) in the pronotum. Larvae are typically hydrocarbons, organophosphates, carbamates, and orange with two rows of black lateral spots, and as pyrethroids. This sustained evolution of pesticide later instars are characteristically hump-backed resistance has prompted development and use of in shape. Colorado potato beetle overwinters as additional novel chemical controls such as neoni- the adult in the soil, and has from one to several cotinoids and ecdysteroids, as well as transgenic generations per year, depending on temperature, crops incorporating high levels of beetle-specific 1010 C Colorado Potato Beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) Colorado Potato Beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), Figure 81 Colorado potato beetle (a) egg mass, (b) larvae, (c) pupa and (d) adult. (Egg mass photo by D. Weber; others by Doro Röthlisberger, Zoological Museum, University of Zurich.) Colorado Potato Beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) C 1011 Cry3A BT toxins (derived from Bacillus thuringi- threshold, but not reliably in most current crop- ensis). Transgenic potatoes were developed and ping systems. Predatory stink bugs (Podisus and introduced as the cultivar “Newleaf” in the 1990s, Perillus) as well as several species of generalist later also incorporating resistance to important Coccinellidae and Carabidae, spiders and harvest- aphid-transmitted potato viruses. Yet this highly men are common predators. During the 1980s, the effective tactic met with a mixed and then negative egg parasitoid wasp Edovum puttleri was intro- reception, first because it was introduced con- duced to the USA from Colombia (where it is temporaneously with an effective and broader- native on L. undecemlineata (Stål)), and enjoyed spectrum systemic insecticide, imidacloprid, and success as an inundative biocontrol in the high- later because large multinational processors value eggplant crop. This parasitoid is not winter- decided that using transgenic potatoes would risk hardy. Rearing efforts ceased with the advent of consumer opposition across their global markets. the systemic neonicotinoid imidacloprid. Two years after registration in the US, major buyers Two of the most promising natural enemies announced plans to discontinue Newleaf purchases, native to North America are quite poorly studied. and commercial sales have been discontinued. Lebia grandis is a carabid ground beetle predator of Transgenic technology continues with limited field Colorado potato beetle eggs and larvae as an adult, trials in eastern Europe, and may be commercialized whose larvae are ectoparasitoids of Colorado potato in the future. One prerequisite for sustainable use, beetle pupae. The newly hatched larvae locate the as with chemical controls, is the implementation of Colorado potato beetle host soon after it buries resistance management plans. itself to pupate, then obtain their entire larval food Periodic failure of chemical controls has requirement from a single host pupa, emerging prompted research into a variety of alternatives weeks later as blue-metallic and orange, very ranging from pedestrian to peculiar. These include mobile and hungry adult predator beetles. Two native and introduced biological controls, crop species of tachinid parasitoid flies of the genus rotation, cover crop mulches, trap crops, trenches Myiopharus