There are several insects that affect maize including earwigs, weevils and armyworms. The most common pest is the European corn borer that led to the development of a form of maize called Bit maize which has proved resistant to these insect.
In the United States, exterminators specialize in removing insects and other pests from homes, businesses, and schools. They also employ prevention strategies when working against insects and pests.
they reduce it
worms
the removal of any pests can affect the food web because another animal eats that pest and if it is removed that animals is going to die shortly.
This contains 10 most common pepper pests/diseases http://www.organicgardening.com/learn-and-grow/how-handle-top-10-most-common-pepper-pests-and-diseases?page=0,1
they do this by spreading diseases and germs to to things and people
H. E. Wave has written: 'Biology of the foxglove aphid in the Northeastern United States' -- subject(s): Potatoes, Foxglove aphid, Diseases and pests
Lee Oras Overholts has written: 'Courses in forest pathology' -- subject(s): Trees, Diseases and pests 'The Polyporaceae of the United States, Alaska, and Canada' -- subject(s): Polyporaceae, Fungi 'Courses in forest pathology' -- subject(s): Trees, Diseases and pests
You need to be more specific. There are literally thousands of individual crop pests. Just for one crop, corn (maize), there are a minimum of six different weeds, four insect species, eight diseases, and three bird species, all of which are pests to that crop.
B. Austin Haws has written: 'An introduction to beneficial and injurious rangeland insects of the Western United States' -- subject(s): Control, Insect pests, Beneficial insects
Yes, in the United States two major invasive pests in the deserts are Russian thistle (tumbleweed) and salt cedar (tamarisk).In Australia the prickly pear cactus is an invasive pest.
Thomas W. Whitaker has written: 'Lettuce production in the United States' -- subject(s): Lettuce industry 'Lettuce and its production' -- subject(s): Diseases and pests, Lettuce