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.
Tenses:
1. 1. Simple Present:
1.
These protect crops against damage from other
insects.
2.
That develop colonies on plants.
3.
The Asian lady beetle eats aphids.
2. 2. Simple Past:
1.
American scientist imported one kind of lady
beetle.
2.
They released them as an attempt to control some
kinds of inspect.