 |
Aphids are a regular
pest of many cotton fields.
Chemical control of aphids is expensive, reduces beneficial predators
and parasitoids, and may fail due to aphid resistance, poor coverage,
and resurgence. Therefore, anything that can help growers save a
chemical application for aphids is valuable.
In 1990
we identified the fungus that rapidly reduced cotton
aphid populations to low levels in Arkansas and other southern
states. Research indicated that we could accurately diagnose the
percentage of infected aphids in cotton fields and predict when aphid
populations would crash due to the fungus. Based on this
information we started the Cotton Aphid Fungus Sampling Service in 1993
with
the cooperation of Extension and IPM specialists in several states. |
|
|
The
service operates as follows: Aphid sampling kits are mailed to
cooperators in May. The cooperator may be a grower, a consultant, an
extension agent or researcher. The service costs nothing to the
cooperator. When cotton aphid-infested fields are encountered,
the cooperator collects aphids and sends them back to our laboratory
via FedEx.
 |
| Preparing
aphid samples for diagnosis in the lab. |
|
 |
Fifty cotton aphids are
randomly selected from each sample and squashed in
lactophenol under cover slips for diagnosing at 200x on a
phase-contrast microscope. |
|
In the
laboratory the aphids are prepared and diagnosed under a microscope.
As soon as
possible (usually within 24 hours) the results are faxed back to the
cooperator and also posted on our website on the internet. When
results indicate that 15% of aphids sampled in a field are infected
with the fungus, it is likely that the aphids will decline soon due to the fungus. When 30-90% of the
aphids are infected with the fungus, the aphid population will
decline. In both of these cases the grower can usually save money
by not applying a chemical for aphid control.
Therefore
the service provides decision makers with additional information that
may help avoid unneeded and expensive applications for insecticides.
We
hope that you will consider this your service and provide us with many
samples and comments that increase its usefulness to you.
|
