Tulare County Citrus IPM Demonstration Project - 2002
Cottony Cushion Scale, Icerya purchasi
Back to Tulare 2002

Cottony cushion scale is best controlled by the predatory vedalia beetle (Rodolia cardinalis).  This scale can become a problem when pyrethroids (Danitol and Baythroid), Esteem, Applaud, Provado, or Admire are sprayed before the vedalia has completely cleaned up the cottony cushion scale.  These insecticides will kill the vedalia and allow the cottony cushion scale population to rapidly increase.  Admire has no effect on cottony cushion scale and so should not be used in blocks that have cottony cushion scale.  Applaud and Esteem will kill some cottony cushion scale, so the problems with cottony cushion scale and loss of vedalia beetle can sometimes be in the orchards that are next to those being treated with Applaud or Esteem.

March-May: Heavy populations of cottony cushion scale were observed in blocks 1, 3, and  7 during February and March.  We released vedalia beetles in all three locations and natural infestations also arrived in April.  Cottony cushion scale were rapidly reduced in these locations by the predatory beetles.  Depending on the citrus thrips and red scale treatments used in blocks 1, 2, and 9, and their effects on vedalia beetles, the cottony cushion scale population may disappear or begin to build in these blocks again during the summer and fall.  
June-July: During June it was difficult to find any live stages of cottony cushion scale.  However, in the July sampling small numbers began to appear in most orchards. If these populations continue to build, we will release vedalia beetles in the fall.
August: During August, the vedalia beetles are not active and several of the orchards (1-3) are beginning to increase in cottony cushion scale numbers.  We plan to release vedalia beetles in these blocks when the weather cools down.  

Percentage of trees infested with cottony cushion scale stages

Orchard Feb Mar  Apr May Jun Jul Aug Sep
Biologically-Based Program (aAphytis releases, rare broad spectrum pesticide use)
1a 55% 80% vedalia 8%* 15% 28% 55% 60%
2a 0 0 vedalia* 3%* 0 3% 15% 10%
3a 33% 35% vedalia 0* 0 8% 10% 10%
Intermediate Program (depend on natural populations of  Aphytis, occasional broad spectrum pesticide use)
4 0 3% 3% 0** 0 0 0 0
5 0 0 0 0** 0 3% 0 0
6 0 0 0* 0* 0* 0 0* 0
7 38% 23% vedalia 0*** 0 3% 5% 5%
Conventional Program (reliance on broad spectrum pesticides)
8 0 0 0* 0* 0* 0 5% 0
9 0 0 3%* 3%*
vedalia		 0 5% 0 10%
10 0 0 0* 0* 0 3% 0* 5%

*2002 Pesticide Treatments
 Site 1: Success (May 13) for citrus thrips
Site 2: Kryocide (Apr 18) for worms, Agri-Mek + 1% oil (May 12) for citrus thrips
Site 3: Success (May 6) for citrus thrips
Site 4: Danitol (May 13) + 1% oil for citrus thrips, Esteem + Dimethoate (Jun 12) for red scale and citrus thrips
Site 5: Lorsban + Success (May 11) for citrus thrips and katydid, Success + oil (Jun 20) for citrus thrips, Esteem (Jul 19) for red scale
Site 6: Kryocide (Apr 22) for worms, Success (May 3) for citrus thrips, Dimethoate + Baythroid (Jun 3) for citrus thrips
Site 7: Baythroid (May 9) for citrus thrips, Success (May 30) for citrus thrips, Applaud (Jun 17) for red scale
Site 8: Dipel (Apr 13) for worms, Baythroid (May 10) for citrus thrips, Esteem (Jun 27) for red scale.
Site 9: Kryocide (Apr 6) for worms, Danitol (May 15) for citrus thrips
Site 10: Success (May 2) for citrus thrips, Lorsban (May 16, Aug 21) for citricola