The leafminer,
Liriomyza sativae
Blanchard, is distributed around the world and is an important pest of vegetables and
ornamentals. Given the resistance potential of the leafminer to current insecticides, the use of resistant plant cultivars and
parasitoids could be effective integrated pest management (IPM) strategies against it. Cucumber (
Cucumis sativus
L.)
is a preferred host for this insect. Seventeen cultivars of cucumber have been evaluated to study resistance mechanisms
to
L. sativae. All cucumber cultivars were evaluated in screening tests in greenhouse with indices such as the number of
leafminer stings, the number of larval mines, the proportion of larval mines to leafminer stings, and the rate of injury.
Significant differences (p < 0.01) were found among cultivars, as well as significant correlations among all evaluated
indices. Cucumber cultivars were ranked by the cluster method based on all measured characters and were classified into
four groups: susceptible, semi-susceptible, semi-resistant, and resistant. Trials of antibiosis resistance of cucumber cultivars
were conducted in a growth chamber and were evaluated with biological indices of insect activity including oviposition
period, larval and pupal duration, percentage of larval and pupal mortality, and the sex ratio among selected cultivars.
Significant differences were found for all indices except pupal weight and the sex ratio. The cultivars were analyzed by the
cluster method based on all measured characters and were divided into three groups including sensitive, slightly resistant,
and semi-resistant. No cultivar was immune to injury.
