Insects and diseases harm our food in many ways. Some weaken or kill plants, others leave behind worms or other damage making the fruit or vegetables inedible.  Farmers must control pests so they can grow healthy food.

If our apple growers couldn’t control codling moths, we couldn’t grow apples in Washington. This moth larva destroys the apple.

(Photo credit, Washington State University)

This little guy may not look like trouble, but he can ruin your fries!  The potato psyllid carries a disease that causes potatoes to have dark stripes through them when they are cooked.

Did you know?
Over 40,000 species of weeds and insects threaten the health and yield of food crops in the United States

Western cherry fruit fly maggots, which develop inside cherries and other fruit, make the fruit unmarketable. During inspection, if even one maggot is detected, a grower’s entire crop can be rejected. In unsprayed trees, a high percentage of fruit is likely to be attacked.

(photo by E.Beers)


Did you know?

An adequate, reliable food supply could not be guaranteed without effective crop protection products

Some 20 - 40 % of the world's potential crop production is already lost annually due to weeds, pests and diseases. These crop losses would be doubled if existing pesticide uses were abandoned. Many fruits and vegetables would be in short supply and the price of food would rise.

Washington State University pioneered integrated pest management in apples.  Most apples growers now use pheromones for mating disruption to help control codling moths.  Twist ties like the one pictured here give off a scent that confuses the male moth so it cannot find females.  This prevents the moths from reproducing.  

This integrated pest management (IPM) method has reduced pesticide use in orchards, but it doesn't always work, an effective insecticide is still necessary - even in organic orchards.

Pheromone dispenser (Mike Doerr)

  Would you eat these potato chips?  They were infected with a disease             carried by the potato psyllid seen to the left.

  (Photo courtesy of Agricultural Research Service, United States Department of Agriculture)

The little corn plant in the center of the picture below is competing with weeds for nutrients, water and sunlight. It will be choked out by the weeds growing around it unless they are removed. It would be very costly and difficult to remove a field of these weeds by hand without also disturbing the growth of the corn plants. 

(photo courtesy of Syngenta)

Did you know?
Organic farmers use pesticides too. "Organic" does not mean pesticide-free

The corn borer larva damages corn. Bt (Bacillus thuringensis) is a common bacterium in soil. It contains a protein that paralyses corn borer larvae. Pesticides made from Bt have been used by farmers worldwide for decades and can be applied to organically grown crops.

Organic farmers also use pesticides because they too must control pests to protect their crops. The list of pesticides approved for organic use is not based on safety criteria but whether the product is “natural.”  “Natural” does not mean safe. Many natural products including nicotine, acetic acid and rotenone can be harmful.  All have been used as organic pesticides.

(photo shows damage caused by potato psyllid)