Pest Management Professional, September 2013

dos donts SPIDERS A lthough unpopular most spiders are cryptic and inert to humans and have chelicerae mouthparts too small or weak to puncture human skin Usually spiders wont attempt to bite unless accidentally trapped or held The jaws of the spider suborder Araneomorphae are slung vertically under the front of the carapace The jaws are tipped with fangs that can inject venom or digestive secretions located below the eyes The fangs are hinged laterally and bite crossways against each other This is an efficient arrangement for seizing and manipulating prey especially on a web Next to the jaws to taste food are its pedipalps which are sensory appendages Male spiders have an enlarged segment on the tip of the pedipalps which are copulatory organs that transfer sperm to the female The pedicel or waist connects the cephalothorax and abdomen The cephalothorax or fused head thorax contains the spiders brain eyes jaws stomach and leg attachments Its abdomen contains its guts heart reproductive organs and silk glands Spinnerets are where spiders silk is released The spiders eyes which detect only light and dark are located on top of the cephalothorax Most have eight eyes but its possible to have 12 six four two or none Its legs consist of seven segments with two or three claws at the tip If a leg is lost itll grow back Treatment strategies Most spider species are beneficial because they eat harmful insects and mites in and around structures so when possible dont unnecessary destroy spiders Other tips are Do interview your client to gather detailed information about spider pressures and possible sources Take notes Dont overlook any detail provided in Q A discovery with your client because the smallest detail will be important to a successful intervention Do maintain sodium vapor yellow exterior lighting to reduce night flying insects that attract spiders Dont maintain mercury vapor blue exterior lighting if possible because its 112 times more attractive to flying insects Do use high pressure water to knock down and destroy webs egg sacs and spiders Dont allow woodpiles trash rocks compost piles old boards and debris to collect along exterior structural areas because they can harbor spiders Do eliminate moisture and humidity by keeping basements and crawlspaces as dry as possible through ventilation and dehumidification Dont allow a buildup of webs egg sacs and spiders Use a vacuum cleaner with the proper attachments to access difficult to reach areas PMP Dr Mitchell D O Ph D M P H B C E a board certified physician and entomologist is principal technical specialist for PestWest Environmental as well as PMPs Technical Editor He can be reached at docmitchell@ northcoastmedia net or 515 333 8923 R oughly translating to unenthusiastic inhabitant Parasteatoda tepidariorum illegally resides with innocent inhabitants of structures As one of the most common infiltrators of architectural spaces the American house spider invades numerous construction types Irregular webs are spun purposefully in corners and angular spaces Oval parchmentlike brown egg cases about 250 eggs per sack with about seven sacs or 1750 eggs in a lifetime are a coarse silk cocoon conspicuous within webbing Co conspiring second instar spiderlings balloon and produce independent webs AHS adult female suspects are 5 to 6mm males are 3 to 5mm There are eight eyes with two proximal pairs The female is yellowish brown on the carapace with a dingy white to brown abdomen Legs are yellowish and pale ringed By contrast a males legs are orange There are pale chevrons on the back These comb clawed vagrants can live more than a year An AHS produces sticky silk stand webs to capture insect victims The assailant waits in an extra silky area of the web If the victim is larger it becomes entangled and more aggressively battered with additional silk and torque Management of pestiferous spider populations is adjudicated through a template of integrated pest management IPM Inspect and investigate for AHS including the structure and exterior premises Identify AHS species Determine occupant tolerance levels Implement multiple control measures cultural physical mechanical and chemical Evaluate intervention effectiveness and make appropriate adjustments Dr Stuart Mitchell t Technical Editor A grass spider Agelenopsis naevia MOST WANTED AMERICAN HOUSE SPIDERS Photos courtesy of and copyrighted by Gene White pmimages@ earthlink net www mypmp net Pest Management Professional September 2013 71