Repellent experiment
The repellent and anti-oviposition effects of plant products
were determined using a spraying test bioassay in greenhouse
condition. The experiment was carried out from 11
January to 24 February 2011 in the Experimental Agriculture
Research and Natural Resource Center of Kerman, Kerman,
Iran. The cucumber plants ‘Negin’ with five fully expanded
leaves were used as host plant and oviposition substrate of
the greenhouse whitefly. The plants were treated with extract
at 40 µL/mL and control plants were sprayed with distilled
water. The essential oils of plant derived above mentioned at
same volume (5ml) (for avoid the phytotoxicity effect on the
cucumber plant) (except C. cyminum and T. vulgaris) were
sprayed on filter paper (Whatman, 9 cm diameter) (The size
of filter paper was sprayed with essential oils: 2 × 4 cm). One
treated filter paper was attached at the each petiole cucumber
plants, via plastic string. Moreover, extract was sprayed
on the plants under the same condition described above with
the same volume (40 mL). Randomly, four treated plants with
the plant products and four control plants were placed simultaneously
in a double row of plants with 18 cm spacing between
and within rows in each cabin of the experiment (80 ×
60 × 60 cm). Into each cage, 250 greenhouse whitefly adults
were released. From each plant, 3 and 6 d after infesting with
T. vaporariorum, one leaf, at the same areas, were detached
to evaluate the repellent and anti-oviposition effects of plant
products. The numbers of the greenhouse whitefly adults and
eggs on each detached cucumber leaf were recorded. At least
two cages were used for each plant product. The repellency
index (RI) and anti-oviposition index were calculated from
the formula (Pascual-Villalobos and Robledo, 1998):