2004 Insecticidal Control Strategies for Scale Pests of Citrus
This summary is based on field trials conducted
by Dr. Beth Grafton-Cardwell and Chris Reagan
at the Lindcove Research and
Extension Center
Back to California Red
Scale
One would think that each insecticide would control all scale species to the
same degree. However, we are finding that this is not true. For
example, Esteem is very effective against California red scale and cottony cushion scale
and not effective against citricola scale. In
addition, the insecticides vary in their toxicity to natural
enemies. The older organophosphate and carbamate insecticides (Lorsban, Supracide,
Malathion, and Sevin) are toxic to wasp parasites needed for California red scale and citricola
scale control and relatively nontoxic to predatory beetles. The new insecticides (Esteem,
Applaud, Admire) are toxic to
vedalia beetles needed for cottony cushion scale control and relatively nontoxic
to parasitic wasps. Depending
upon the combination of scale species present in your orchard, and the level of
integrated pest management you are trying to achieve, you must make a different
choice as to which insecticide is most appropriate. Of course, the level of control
achieved by these insecticides also depends upon the application
method (nozzles, speed, rate, timing, and water volume) as well as the level of insecticide resistance in the pest.
Target Pest
|
Lorsban,
Sevin, Supracide, and Malathion |
Narrow Range Oil
|
Esteem
|
Applaud (buprofezin) |
Provado |
Admire |
Assail (acetamiprid) |
|
|
Organophosphate
and carbamate |
Petroleum
oil |
Insect
growth regulator |
Insect growth regulator |
Neonicotinoid |
Neonicotinoid
soil application |
Neonicotinoid Foliar |
|
Citricola
scale |
Excellent |
Low
Control |
No |
Slow, Moderate Control |
Moderate |
Moderate |
Moderate Control |
|
California
red scale |
Excellent
Control if resistance is not a problem |
Good |
Excellent
Control |
Moderate Control |
No |
Moderate Control |
Low Control |
|
Cottony
cushion scale |
Moderate to Excellent
|
Low |
Slow, moderate control |
Slow, Moderate Control |
No |
No |
No Control |
|
Impact on natural enemies |
Kill most natural enemies, especially parasitic wasps. Lorsban is the least toxic of the group |
Kills
only those natural enemies it comes in direct contact with |
Kills
vedalia eggs and pupae for 5-6 months |
Kills vedalia pupae for 2-3 months |
Kills
most natural enemies for 1 month |
Kills
vedalia larvae and adults for 4-6 months |
Kills most natural enemies for 1 month |
Excellent: long-term (multiple-year) control of scale on all plant parts
Moderate: Shorter-term (single year) control or suppression
Low: Insufficient to provide economic control