Larger grain borer Prostephanus truncatus Fig 53a g

Adults are 8-10 mm long. The body is elongate and cylindrical, dark brown and has a smooth polished surface. Eggs are laid in batches or singly on the grain; fecundity is 300-500 eggs. Development from egg to adult is about 27 days at 32 °C and 80% RH, and 78 days at 22 °C and 50% RH. At 70% RH the development period increases from 30 days at30 °C to 40 days at 35 °C, and to 61 days at 22 °C. It often attacks maize before harvest and continues to infest during storage. It is capable of feeding on wheat, rice, cowpeas, beans (Phaseolus), peanuts, cocoa beans, and coffee beans. Although the immature stages do not feed on wood, adults produced from larvae that bored into wood live longer than those adults deprived ofwood as a substrate for pupation. P. truncatus can survive for long periods in wooden bins and in cobs and stalks of maize. This species is established in most tropical regions and is a pest in Central America and Africa.

Lessergrain borer, Rhyzopertha dominica (Fig. 5.3c, h) Adults are about 5 cm long. The body is dark brown or black, and has a somewhat roughened surface. Eggs are laid in batches on the kernels of grain or singly in the loose frass produced by the feeding adults and larvae. Fecundity is 300-400 eggs; hatching is in about 32 days at 18 °C, and about 5 days at 36 °C. Firststage larvae cannot bore into undamaged seeds. Second-stage larvae are capable of directed movement, but the third and successive stages are C-shaped and incapable of movement on a flat surface. Larvae develop in whole grain and remain within the kernel through four or five instars; on wholemeal there are 2-7 instars. There is a reduction in the number of instars and an increase in development time at about 28 °C. Larval development on wholemeal at 70% RH requires 29 days at 28 °Cand46 days at 25 °C. Pupation usually takes place in an enlarged cell in the larval feeding tunnel. At 70% RH the pupal period is 5 days at28 °C and 8 days at 25 °C. The adult remains in the cell for 3-5 days before emerging. Development from egg to adult takes about 25 days at 34 °C, and with 22% larval mortality; and 84 days at 22 °C with 53% larval mortality; and 36 days at38 °Cwith86% larval mortality. Adults readily fly but their flightis notwell oriented, and air currents carry them. This species feeds primarily on cereals and products made of these and other grains. It commonly infests flour, macaroni, beans, chickpeas, seeds, edible bulbs, grains, and sometimes wood. Damage from R. dominica can be considerable because adults and larvae feed on the surface and interior of grains. It can bore into wooden objects. This species is widely distributed.

Lead-cable borer, Scobicia declivis Adults are 5-6 mm long, reddish brown, and the body is somewhat cylindrical. The pronotum has rasplike teeth or projections at the front; antennae are eight-segmented, and there is a three-segmented club. Females bore a small tunnel and deposit eggs inside it. Larval development requires about 9 months, and the pupal period lasts about 2 weeks. Adult beetles remain in the pupal chamber for several weeks before emerging to the wood surface. There is one generation per year. It normally infests seasoned oak, but also acacia, eucalyptus, maple, elm, chestnut, and other hardwoods. It has been reported attacking newly painted houses, and damaging wine casks, hardwood paneling, and flooring. The common name is derived from the ability of the adults to bore through the lead sheathing ofaerial telephone cables, making holes about 2.5 mm wide. Most activity occurs from June to August, when beetles emerge in large numbers. Damage usually occurs later, when moisture enters the cables, causing short circuits. Adults are stimulated by heat, and sometimes bore into roofing materials because of high temperatures. Attacks on asphalt roofing and lead cables may be linked to local forest fires, particularly in stands of oak, where the beetle occurs in large numbers. This species is common along the coast of California and southern Oregon.

Cylindrical auger beetle, Xylion cylindricus Adults are 5-7 mm long, dark brown to blackish brown. The prothorax has small lobes atthe base of the antennae; the antennal club is three-segmented, and the posterior margins of the forewings are produced into short, rounded lobes. Emergence holes are round and about 3.5 mm diameter. This species infests the sapwood portion of hardwoods. It often attacks wooden wine casks, and wine is lost through holes bored by the adults and larvae. It is distributed in Australia.

Red-shouldered shothole borer, Xylobiops basilaris Adults are about 5 mm long and black; the basal third of elytra is reddish brown. The body is cylindrical and the pronotum has rasp-like projections. The elytra posterior third is concave and there are three spines on each side. Eggs are laid singly in holes bored through the bark into the sapwood. Eggs hatch in about 10 days and the C-shaped larvae feed in the sapwood and sometimes the heartwood portion of infested wood. Galleries extend with the wood grain and they are filled with fine, powder-like frass. Development from egg to adult takes about 2 years, and adults emerge after the wood has been processed into furniture or other products. The adult attacks recently felled or dying hardwood trees and logs. The larvae feed in the sapwood portion and can cause considerable damage. Hickory, persimmon, and pecan are most frequently infested, but other hardwoods in use, such as rustic furniture, fences, small tools, and tool handles, are infested. It has been found in lumber shipped to the UK. Larvae of a related species, X. quadrispinosus, are frequently found in hardwoods in southwestern USA. This species is common in eastern and southern USA.

Other Bostrichidae Stephanopachys rugosus often infests bark-covered floor joists, and freshly cut or recently milled pine. Larvae complete development in 1 year, but take up to 5 years in seasoned wood. A related species, S. substriatus, attacks pine, hemlock, and fir; infestations occur in furniture and in con-structionlumber. Scobiciabidentata feeds in freshly cutwood and lumber of several hardwood species. Tropical and subtropical Bostrichidae are wood borers, and often encountered in food and produce stores in structural wood; the adults are found boring into stored foods. These include Apate spp., black borers, which are distributed in Africa, Israel, and tropical South America, and Bostrychopis parallela, black bamboo borer, which occurs in Southeast Asia.

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