This is Steve Ember with the VOA Special English AGRICULTURE REPORT.
There are lots of insects that farmers hate. But there also are some they like. These protect crops against damage from other insects. A good example is the lady beetle, also known as the ladybug.
Lady beetles are a natural control for aphids. Aphids are tiny insects that develop colonies on plants and eat plant fluids. Aphids can also spread crop diseases. Adult lady beetles can eat fifty aphids a day. The young beetle larvae can eat hundreds of aphids.
Lady beetles are red, orange or black. They often have black spots, though some have light colored spots. Different kinds of lady beetles have different numbers of spots. There are lady beetles with four, five, seven and fourteen spots.
Many of the well-known kinds of lady beetles come from Asia or Europe. They now are common throughout the United States.
American scientists imported one kind of lady beetle, the multicolored Asian lady beetle, as early as nineteen-sixteen. They released them as an attempt to control some kinds of inspects. Over the years, the beetle has become established, possibly helped by some that arrived with imported plants on ships.
Experts say over four-hundred-fifty kinds of lady beetles are found in North America. Some are native to the area. Others have been brought from other places. Almost all are helpful to farmers. Two kinds, however, are not. The Mexican bean beetle and the squash beetle eat plants.
The Asian lady beetles now in the United States probably came from Japan. The Asian lady beetle eats aphids that affect crops like soybeans, fruits and berries.
In the southern United States, Asian lady beetles have reduced the need for farmers to use pest-killing poisons on pecan trees. This popular tree nut suffers from aphids and other pests that the beetles eat.
But some people say the Asian lady beetle has itself become a pest. This time of year, lady beetles have no food after crops have been harvested. It is time for them to prepare for winter. Normally this is in the ground, but it can also be in someone's home. Some farmers also worry that the beetles may eat their late-autumn fruit crops.
Experts say Asian lady beetles may appear in large numbers in some years. But they say the insects are too helpful to consider pests.
This VOA Special English AGRICULTURE REPORT was written by Mario Ritter. This is Steve Ember.