Pests

1. Selected Insect Pests  
2. Selected Arachnid Pests  
3. Selected Rodent Pests

Selected Insect Pests  

pest = a non-human organism harmful to human interests

vector = a pest that transmits disease

A. arthropods: it is incomplete to talk only about insect pests --
                                     arthropods include insects, arachnids, and others: 
      
                       insects   (roaches, fleas, flies, mosquitoes, lice)                                                                       
                       arachnids (ticks, mites, spiders)                                                                  
                       others    (myriapods, diplopods, crustaceans)               
                                                                                                                                                                              
   Insect Pests                          
                                                       
B. Roaches:  Roaches are tough to kill for many reasons, but perhaps 
               foremost is that the eggs are resistant to most pesticides 
               and usually the most difficult stage to kill. 

   1. American         Pareplaneta americana                           
      cockroach:       large (about 1.5 inches)              
                       reddish brown                                                                                  
   2. Oriental         Blatta orientalis                           
      cockroach:       about 1 inch                          
                       brown or black  
                       (sometimes called a "waterbug",
                        because it prefers dark, wet areas).                                                          
   3. German           Blatella germanica                               
      cockroach:       medium (about 1/2 inch)               
                       light brown                                                                                    
   4. Brown-banded     Supella longipalpa                          
      cockroach        medium (about 1/2 inch)               
                       light brown with darker                           
                       brown bands across abdomen                        
                                                                                                                     
C. Fleas:                                                                  
                                                                       
   5. Cat Flea:        Ctenocepalides felis                  
                       not normally a vector                                                                          
   6. Dog Flea:        Ctenocepalides canis                  
                       not normally a vector                                                                          
   7. Oriental         Xenopsylla cheopis                    
      Rat Flea:        spreads plague, etc.                  
  
D. Flies:                                                                  
                                                                                                 
   1.  House fly:         Musca domestica                                                                                             
   2.  Lesser             Fannia                              
       House fly:                                                                                        
   3.  Stable fly:        Stomaxys                                                                                           
   4.  Bottle fly:        Caliphora                           
       (or Blow fly)                                                                                                       
   5.  Flesh fly:         Sarcophagidae                                                                                  
   6.  Horse fly:         Tavanus
       (or gadfly)
   7.  Vectors:           Tsetse fly:    Glossina
                          Black fly:     Similium                                                                        
   8.  Ash whitefly:      not a true fly (related to aphids)            
                                                              
                          waxy coating prevents               
                             absorption of insecticide                                                                      
                          no natural enemies in California     
E. Mosquitoes:                                                           
                                                                             
   9.  Anopheles:         transmits malaria                             
                          Anopheles quadrimaculatus
                          Anopheles albimanus
                          Anopheles freeborni 
   10. Culex:             Culex pipiens                      
                          Culex tarsalis                                                                                  
   11. Aedes:             Aedes aegypti                      
                          Aedes albopictus                   
                                                             
F. Lice:                                                                 
                                                                        
   12. head lice:         Pediculus humanus capitis                                                                                                                                         
   13. crab lice:         Pthirus pubis                      
                          pubic lice                                                                                                                                                                             
   14. body lice:         Pediculus humanus corporis                  
                          body lice is a major vector most associated with 
                          microbial agents of disease                    
 
 
                       
                                           

Selected Arachnid Pests

 
A. Ticks:    ticks must attach to their human host for several hours 
              in order to transmit a variety of diseases 
              (including Lyme Disease and Rocky Mountain Spotted Fever).
              This characteristic means that removing attached ticks in 
              a timely manner really can lower the risk of these diseases.
                                                                   
   1. hard ticks:  Ixodidae:                                                                                                            
                   Ixodes dammini
                   Ixodes pacificus                                                                   
                   Dermacentor andersoni
                   Dermacentor variabilis
                                                                   
   2. soft ticks:  Argasidae:                                                                                                           
                   Ornithodoris hermsi
                   Ornithodoris coriaceus
                                                                                                                                       
B. Mites:                                                          
                                                                   
   3. chiggers:    larval stage                                      
  
C. Spiders:
 
   4.  black widow 
   5.  brown recluse
 
  
  

 

Selected Rodent Pests

      1. Rats      

There are two main species that live in closest association with humans (and therefore are most associated with disease):

• Rattus norvegicus (also called the Norway rat, sewer rat, or wharf rat); and
• Rattus rattus (also called the roof rat, ship rat, or fruit rat).

The first picture shown below is Rattus norvegicus (also called the brown rat, although color is not a reliable way of identification). Take a close look at the ears, the nose, and the tail of this rat, because it is important for identification purposes.

Now look at the second species of rat that lives close to humans: Rattus rattus (sometimes called the black rat, but once again the color is not a reliable means of identification). In comparing the two rats, note the following differences with Rattus rattus:

• The ears are bigger with Rattus rattus
• the tail is longer with Rattus rattus (longer than the body of the rat)
• the nose is a bit more pointed with Rattus rattus.

The tail is an especially important feature, because it gives the roof rat better balance. It tends to live above the ground as evidenced by its various nicknames (the roof rat, the fruit rat). The Norway rat tends to be larger and more aggressive than the roof rat, and the two species are mortal enemies. Lab rats and pet rats are domesticated versions (through selective breeding) of Rattus norvegicus.

From a biologist's standpoint, rats have some pretty amazing attributes:

• They are prolific: they reproduce quickly
• They are smart: "quick kill" rodenticides don't always work well with groups of rats
• They are surprisingly tough: while cats can obviously kill rats, cats tend to prefer smaller prey such as mice.

 
 
      2. Mice 
 

Mice are natural enemies of rats. They have many of the same attributes as rats, but mice can pass through 1/2 inch diameter holes, making them better at gaining entry into buildings. Mice populations may increase if rat populations are controlled.

Despite our cultural fascination with mice (e.g., Mickey Mouse), mice can be just as dangerous as rats at passing along diseases. The most common mouse pest in homes, Mus musculus, is shown below.

(Mus musculus -- common house mouse)
 

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