7
 prey : predator com lex has been established, but this needs further
 investigation.

 The lowest recommend ed rate should be applied and combinations of pesticides
 should be avoided w en possible. Once stability in the spider mite : predator
 population has been achieved, application of the "intermediate" insecticides
 may be possible when carefully timed and applied. According to our present
 knowledge, from Marc onward, the chances for an upsurge of a mite population
 under biological control is small, thus opening a period when more toxic
 pesticides could be considered. Also, the dense leaf canopy provides a refuge
 for some of the predators to survive. More detailed investigations are needed
 to clarify this.

 Some insecticides are extremely poisonous to predators, for instance, Lannate,
 Sevin (carbaryl), Thi dan endosulfann) and Vydate (oxamyl). They also have a
 long residual action nd are incompatible with biological control.

 The present knowledge n pesticides that may be compatible with biological
 control by Ph. persimi is in strawberry crops is summarized in the following
 table.

 Table 2. Safe (S) and intermediately (I) safe pesticides for use with Ph.
 persimilis p datory mites in strawberry crops.


 Common name Trade name Effect PHI

 Bacillus thuringiensis Javelin, etc. S 0
 Fenbutatin-oxide, Hexaki Vendex S 1
 Captan 50W Captan S 0
 Copper Various coppers S 0
 Fosetyl-Al Aliette S 0
 Ipridione Rovral S 0
 Sulphur Various sulphurs S 0
 Thiram Thiram S 3
 Avermectin Agri-Mek I 3
 Diazinon Diazinon I 5
 Malathion Malathion I 3
 Mevinphos Phosdrin I 2

 PHI = the number of days t at must elapse between application and harvest


 Summary
1. Monitor spider mite p pulations, starting with the nursery stock.

2. Do not apply Benlate, Topsin, Lannate, Thiodan, or Sevin prior to
 releasing the predato s.