sodininkystė ir daržininkystė 25(4)

Discussion. Meteorological conditions for strawberry mite development were
favorable in 2005 and averagely favorable in 2006. High air temperature and dry
weather resulted higher infestation of strawberries by mites in 2005.
The effect of the lower rate of Abamectin on strawberry mites was weaker.
Abamectin 18 g l -1 , 21.6 g AI ha -1 was from moderately to very toxic 3 and 7 and
slightly toxic 21 days after treatment, meanwhile Abamectin 18 g l -1 , 18.0 g AI ha -1
was only moderately toxic 3 and 7 and slightly toxic 21 days after treatment. The
field rate (9.0 g AI ha -1 ) of Abamectin 18 g l -1 was slightly toxic 3, 7 and from nontoxic
to slightly toxic 21 days after treatment. The toxic effects of pesticides to
mites depends on the chemistry of pesticides, their rates, microclimatic conditions
and the development stages of the mites (Edland, 1994; Auger et al, 2003; Hardman
et al., 2003; Bostanian et al., 2004; Martînez-Villar et al., 2005). Similar toxicity
patterns of different rates of Spirodiclofen to strawberry and two spotted spider
mites were recorded in strawberries (Raudonis, 2005, 2006). This study shows that
the toxicity of Spirodiclofen 240 g l -1 , 96.0 g AI ha -1 was similar to the toxicity of
Abamectin 18 g l -1 , 21.6 g AI ha -1 to strawberry mite, except that Spirodiclofen had
longer term of action.
The toxicity of Lambdacihalotrin 50 g l -1 , 25.0 g AI ha -1 was similar to Abamectin
18 g l -1 , 9.0 g AI ha -1 . Lambdacihalotrin 50 g l -1 , 25.0 g AI ha -1 was slightly toxic
to strawberry mites after 3 and 7 days, meanwhile it was non-toxic 21 days after
treatment in 2005. Lambdacihalotrin 50 g l -1 , 25.0 g AI ha -1 did not affected strawberry
mite in 2006, on the contrary, it was observed that the number of mites was
statistically higher after Lambdacihalotrin treatment in comparison with unsprayed
plots. The toxic effect of Lambdacihalotrin on the predatory mites Amblyseius andersoni
Chant, which is a natural predator of strawberry mite, was recorded (Raudonis,
2006). Similar results have been recorded in apple-trees (Raudonis et. al.,
2004). The control of Phytophagous mites using Phytoseiid mites, has been demonstrated
in different crops (Roy et al., 1999; Prischmann et al., 2001; Osakabe,
2002; Pratt et al., 2002; Badii et al., 2004; Harmon, Andow, 2004).
Conclusions. Abamectin 18 g l -1 , 21.6 g AI ha -1 was from moderately to very
toxic 3 and 7 days and slightly toxic 21 days after treatment. Abamectin 18 g l -1 , 18.0
g AI ha -1 was only moderately toxic 3 and 7 days and slightly toxic 21 days after
treatment. The field rate (9.0 g AI ha -1 ) of Abamectin 18 g l -1 was slightly toxic 3 and
7 days and from non-toxic to slightly toxic 21 days after treatment. The toxicity of
Lambdacihalotrin 50 g l -1 , 25.0 g AI ha -1 was similar to Abamectin 18 g l -1 , 9.0 g AI
ha -1 , meanwhile the toxicity of Spirodiclofen 240 g l -1 , 96.0 g AI ha -1 was similar to
the toxicity of Abamectin 18 g l -1 , 21.6 g AI ha -1 to strawberry mite.
Gauta 2006-11-15
Parengta spausdinti 2006-12-11
References
1. Auger P., Guichou S., Kreiter S. Variations in acaricidal effect of wettable sulfur on
Tetranychus urticae (Acari: Tetranychidae): effect of temperature, humidity and life stage //
Pest Management Science. 2003. 59(5). P. 559–565.
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