Insecticidal Activity of Jatropha Extracts Against the Azalea Lace Bug, Stephanitis pyrioides (Hemiptera: Tingidae).

Area of Science:

• Agricultural Science
• Entomology
• Plant Science

Background:

• The azalea lace bug (Stephanitis pyrioides) is a significant pest of ornamental plants.
• Current pest control methods may have environmental drawbacks, necessitating exploration of natural alternatives.

Purpose of the Study:

• To evaluate the insecticidal bioactivity of ethanolic extracts from 35 Jatropha L. species against the azalea lace bug.
• To identify Jatropha species with potential for biopesticide development.

Main Methods:

• Ethanolic extracts were prepared from stem, root, and whole plant material of 35 Jatropha species.
• Extracts were formulated into emulsions with de-ionized water and 10% dimethyl sulfoxide (DMSO).
• Bioassays were conducted using adult S. pyrioides exposed to varying extract concentrations in a 96-well microtiter plate format, following a randomized complete block design (RCBD).

Main Results:

• Extracts of Jatropha clavuligera and J. ribifolia demonstrated high bioactivity, with mortality rates exceeding the positive control, azadirachtin, at concentrations from 0.06% to 0.50%.
• At 1.00% concentration, J. clavuligera, J. ribifolia, and azadirachtin achieved 100% bug mortality within 3 hours.
• Jatropha clavuligera exhibited the lowest LC50 and highest insecticidal potency, causing ≥98% mortality within 3 hours.

Conclusions:

• At least five Jatropha species possess active ingredients in their stem, root, or whole plant extracts that are effective against adult azalea lace bugs.
• These findings support the potential of Jatropha species as a source for novel, natural biopesticides.