Controlling disease- carrying cockroaches in swine barns
By Mike Catangui, Ph. D
Cockroaches are carriers of disease-causing microorganisms
Table 1 lists three very important bacterial diseases that can be spread by cockroaches in swine barns. In addition, certain proteins (allergens) found in the body and excreta of cockroaches can elicit allergic or asthmatic responses in sensitive humans.2 It is not known whether allergens from cockroaches can also elicit allergic responses in pigs.
The German cockroach (Blatella germanica) [Fig. 1] is the main species associated with swine production in the United States. Cockroaches are considered insects of high public health significance; urban establishments with a visible cockroach infestation are usually perceived as having sanitation issues. The general public has a very low tolerance of cockroaches under any circumstances.
The biology and behavior of cockroaches make them an efficient vector of diseases
Cockroaches crawl over and feed on the secretions and excrements of pigs; they can carry disease-causing microorganisms from these materials directly to the animals, or by contaminating water and feed.
Cockroaches undergo gradual metamorphosis where the immature stages (nymphs) look similar to the adults but smaller in size and lacking fully-developed wings [Fig. 1]. Immature and adult cockroaches have similar nocturnal feeding habits in infested buildings. The German cockroach goes through the egg stage, seven nymphal instars, and reproductive adult stages in about two months (60 days). It is the fastest-reproducing cockroach species found in animal and human dwellings.
Fig. 1. German cockroaches (Blatella germanica) in a barn showing all stages of development (egg pods or ootheca, nymphs, and adults). Photo by Mike Catangui.
Cockroaches can disperse to far distances
The main entry route of cockroaches into a farm may be through human transport of infested materials. Cockroaches (egg pods, nymphs, and adults) can “hitch a ride” on animal feed, human food, groceries, mailed packages, and animal transport vehicles, among others. In this manner, clean farms can be infested by cockroaches coming from many miles away. The egg pods or ootheca of cockroaches can be inserted or "glued" by adult female cockroaches in paper boxes and many other packaging materials. They then hatch out as cockroach nymphs on the farm.
Effective and economical cockroach control products are available to swine producers
There are several effective and relatively inexpensive cockroach insecticides to choose from [Tables 2-5]. To immediately reduce existing cockroach numbers in the hog barns, apply a quick knockdown spray [Table 2] using recommended spray equipment [Table 6] that can apply the rates specified on the label. Quick knockdown sprays [Table 2] can be applied in the hog barns with the animals present. In addition, cockroach baits and aerosol sprays [Table 3] can be deployed in cracks and crevices or otherwise inaccessible areas of the hog barn where cockroaches tend to hide.
During barn clean out or when the pigs are not in the barn, insecticides with longer residual effects can be applied on the surfaces of the empty barn where cockroaches tend to congregate. Cockroach insect growth regulators (IGRs) [Table 4] and empty-barn residual sprays [Table 5] can provide months of residual cockroach control. Although the barns need to be empty of pigs to safely treat with cockroach insect growth regulators and empty barn residual insecticides, the animals can be placed immediately in the treated barns once the spray has dried out. Cockroach insect growth regulators disrupt the normal molting process of immature cockroaches (nymphs), while empty-barn residual insecticides are pyrethroids that kill adults and immature cockroaches alike on contact. Prior to using any product mentioned in this article, carefully read and follow all available instructions, warnings, and safety information made available by the product’s manufacturer.
- A cockroach can live for a week without its head. Due to their open circulatory system, and the fact that they breathe through little holes in each of their body segments, they are not dependent on the mouth or head to breathe.
- Without a mouth, the roach can't drink water and only dies because of thirst.
- Cockroaches can run up to three miles in an hour, which means they can spread germs and bacteria throughout a hog barn very quickly.
- Newborn German cockroaches become adults in as little as 36 days.
- A one-day-old baby cockroach, which is about the size of a speck of dust, can run almost as fast as its parents.
- Because they are cold-blooded insects, cockroaches can live without food for one month, but will only survive one week without water.