Wes Watson North Carolina State University

Publish Date: April 30, 2012

Sarcoptic mange is caused by a microscopic parasitic mite (Figure 1) that lives and feeds in tunnels in the epidermal skin layer of the host (Davies and Moon 1990). Using digestive enzymes to dissolve the host tissues these mites expand their tunnels as much as 3-5 mm per day. Male and female mites usually mate on the surface of the skin. Soon after mating, the newly fertilized female constructs a new feeding tunnel in which to lay up to 3 eggs per day over a 2-3 week period. Generally the eggs hatch in 3-5 days. The larvae continue to expand the feeding tunnels for about 2-4 days before becoming nymphs. Nymphal mites continue to develop 4-6 days before becoming adults. Mite life stages consist of egg, a six legged larva, followed by 8 legged nymph and adult stages. The life cycle from egg to adult takes about 10-14 days and occurs entirely on the host. Mite transmission is primarily by direct contact with infested pigs.

Publish Date: April 26, 2012

The hog louse is one of the largest members of the suborder Anoplura, a group of bloodsucking insects infesting swine (Figure 3). Restricted to the skin surface, hog lice take several bloodmeals each day. The louse is equipped with large claws to grasp the hair allowing these insects to move about the host. Each active life stage resembles the adult except that they are smaller in size. Gravid females glue their eggs to the base of the hair shaft (Figure 3). The eggs hatch into nymphs after incubating about 10 to 14 days. In cool weather hatching may be extended up to 20 days. Nymphs have the same feeding habits as adult lice. After undergoing 3 molts over a 10 to 14 days period, the nymph develops into an adult. Although growth and development is temperature dependent under optimal conditions the entire life cycle from egg to adult can be completed in about 3 weeks.

Publish Date: April 30, 2012

The house fly is the most common nonbiting fly species encountered in swine facilities. Female flies deposit their eggs in manure, spilled feed, or other decaying organic matter found in and around the facility. These eggs typically hatch in 1 to 2 days. Larval development progresses through 3 phases called instars over the next 4 to 6 days. Late 3rd instars will abandon the moist habitat of the breeding site to seek a drier environment in which to pupate. Adults subsequently emerge from the puparium in about 3 to 5 days. The entire life cycle can be completed in as little as 10 to 14 days, depending on temperature. In northern climates house flies are usually present from May through October with multiple generations being produced during the fly season. In southern climates or in temperature controlled swine barns, conditions allow house flies to breed throughout the year.

Publish Date: April 30, 2012

The stable fly is a common biting fly found inside and out of swine facilities. Both male and female stable flies take 1-2 bloodmeals daily and are frequently observed resting in shaded areas while they digest their meal. Females deposit 80-100 eggs in decaying organic matter, typically wet bedding, wasted feed, and mixtures of manure and straw or other bedding. Developmental time of the stable fly is about 15-30 days, the eggs hatch in 1 to 2 days, followed by a 10-15 day larval stage. The larvae then seek a drier environment in which to pupate. Adults subsequently emerge about 6 to 8 days later. In cool climates stable flies are usually active from May through October with numerous generations being produced during this time period. However, in warmer climates conditions allow the stable fly to breed continuously year around. Although stable flies may be infected with PRRS virus under laboratory conditions, the likelihood of transmission is low (Rochon et al. 2011).

Publish Date: April 30, 2012

The cockroach has become an increasingly important pest in swine production in recent years (Waldvogel et al. 1999). The female cockroach deposits eggs in a protective case called an ootheca. The oriental cockroach, Blatta orientalis, deposits the ootheca within a few days. The german cockroach, Blattella germanica, however carries the ootheca for several weeks, limiting the potential for predator or parasitoid attack. Gregarious by nature, cockroaches feed on a variety of foods, including animal feeds and feces.