| dc.description.abstract | The overall objective of this study was to establish a cost effective and
environmentally friendly control strategy of the red spider mites, Tetranychus spp, in
tomatoes using Oberon 240SC and D-C- Tron Plus mineral oil. The efficacy of the two
products, their mixture and a rotation was tested against the red spider mites (T.
evansi, Baker and Pritchard) in the laboratory, green house and field conditions. The
effect of the treatments on the beneficial capacity of the predatory mite (Phytoseiulus
persimilis Athias Henriot) was also assessed in the laboratory and the mite species
associated with the damage and loss on tomatoes in major tomato growing areas in
Kenya were identified.
The ovicidal effect of Oberon 240 SC on the red spider mite (T. evansi) was 100%.
The product however did not have acute toxicity on the motile stages of the mites, but
completely deterred the adult females from laying eggs. D-C- Tron Plus caused
mortality to the motile stages and reduced the percentage of eggs that hatched. The
results for the mixture and the rotation were similar to those of Oberon 240SC alone.
All the treatments were incompatible with the P. persimilis. Both in the green house
and the field Oberon 240 SC, its rotation and mixture with D-C- Tron Plus showed
very high ability to reduce the mite population and the results compared well with
Dynamec 1.8EC a standard acaricide. The effect on fecundity of the mites and the
ovicidal activity of Oberon 240SC lowered the mite population drastically in the field
conditions.
The mites species associated with damage on tomatoes in Loitokitok, Kimana, Rombo
and Maili Tatu areas of Kajiado District were a mixed population of T. evansi and T.
urticae (Koch), while in Mwea, in Kirinyaga District T. urticae was found. In Subukia
and Bahati of Nakuru District T. evansi was identified. | en |
