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Biting Insects & Spiders

Below is a table describing different biting bugs and spider varieties in Delaware that you may wind up seeing in or around your home at some point. The table will help you identify and learn about control methods for removing them from your property.

Species What size & color are they? How do you tell them from other insects? Where are they found in the house? What do they eat? How should you inspect? What can the homeowner do? What should the professional do?
BED BUGS 3/16 inch.  Brown to reddish brown in color. Bed Bugs are flat and oval.  This shape allows them to crawl into cracks & crevices and under ticking on mattresses. Where people sleep.  Bed Bugs are transported to new places in luggage.  Check hotel rooms before you settle in. Blood (human).  Fortunately Bed Bugs do not carry disease.  Their bites may cause itching, but are not considered a medical issue.  But keep in mind that any rash may become infected and require a doctor's attention. If you find dots of dried blood on your bed linens in the morning, start looking under mattress ticking & buttons.  Look where wood pieces of the bed frame join.  Look behind wall hangings and under peeling wall paper. If you find evidence of Bed Bugs, you must call a professional.  If you dispose of your mattress or other furniture, do so in such a way that the items are destroyed.  Do not leave on the sidewalk for others to pick up and spread the infestation.  Bed Bug infestations are not a sanitation issue.  Cleaning your house will not eliminate the infestation.  The fact that you have Bed Bugs is no reflection on your house keeping. After a thorough inspection to find all sites, the professional should apply a labeled insecticide.  The professional may steam-treat the mattress.  It will take several treatments to eliminate the infestation.  Be patient.
FLEAS 1/8 inch.  Brown to black, but reddish black when the body is filled with blood The flea body is laterally flattened.  Fleas have no wings.  They can easily jump. Fleas are found in areas that pets inhabit. Adult fleas are blood-feeders.  Flea larvae feed on feces that the adult fleas drop from their host and organic debris that the larvae find in carpets and cracks in wood floors. If you see a few fleas in your house or on your pet, you can assume you have more. Flea control is a 3-part treatment.  All 3 parts must be done at the same time.  You must treat the host animal (your pet).  You must treat your house inside where your pet spends most of their time.  And you must treat the outdoor areas where your pet spends the rest of their time.  A flea collar and treatments by a vet will help control fleas on your pet.  The homeowner needs to follow the directions of the Pest Management Professional to prepare the house for professional treatment. Your professional will know where in your house and outdoors to treat for fleas.  The professional will use an insect growth regulator that will interrupt the life cycle of the fleas.
BROWN RECLUSE SPIDER 1/4 - 1/2 inch.  Brown with characteristic "violin" marking Most spiders have 8 eyes.  Brown Recluse have 6 eyes in 3 pairs. These spiders are reclusive, hence the name.  They will be in undisturbed areas of the house. All spiders are predaceous and eat insects Brown Recluse are not known to be east of Tennessee/ Kentucky.  However, at least 2 specimens have been recorded from Delaware.  You should shake out shoes and other items that have been in storage before you put them on. Be aware that Brown Recluse can be brought into the state from those states in the distribution of Brown Recluse. If Brown Recluse are found, the professional should conduct a through inspection including wall voids and utility access panels.  The professional should place sticky traps in areas known to be favorable to Brown Recluse to allow targeted pesticide application.
BLACK WIDOW SPIDER 1/3 inch.  Black with characteristic red marking Red "hour glass" on the underside of the abdomen. In dark undisturbed areas.  Basements are favored habitats.  Also near night lights that attract insects. All spiders are predaceous and eat insects Check dark areas in the basement.  Check around night lights.  Always look where you are putting your hands in the basement or tool shed or greenhouse. Be aware of where Black Widows are and where they can be.  All spiders are beneficial.  Black Widows are removing insects from your home and are beneficial insects when left alone. If Black Widows are in great numbers or in the upstairs living quarters, the professional will know how to inspect for them and what pesticides to use to remove them.


Original Publication Date:

Cooperative Extension Education in Agriculture and Home Economics, University of Delaware, Delaware State University and the United States Department of Agriculture cooperating. Distributed in furtherance of Acts of Congress of May 8 and June 30, 1914. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age, or national origin.

Disclaimer: Reference to commercial products or trade names does not imply endorsement by University of Delaware Cooperative Extension or bias against those not mentioned.

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