The document discusses techniques for screening crops for resistance to important insect pests in semi-arid tropical regions. It describes standardized techniques used at ICRISAT to screen sorghum, pearl millet, chickpea, pigeonpea, and groundnut for resistance to shoot fly, midge, stem borers, head bugs, pod borers, leaf miners, and tobacco caterpillars. These techniques include infester row, cage, detached leaf, interlard fishmeal, and artificial infestation methods. ICRISAT uses these techniques to evaluate germplasm and breeding lines for resistance to develop cultivars suitable for subsistence farming in semi-arid tropical areas.

1. Techniques to Screen for Resistance to Insects
Sorghum shoot fly (Atherigona soccata), stem borers (Chilo, Busseola, and Diatraea), midge (Stenodiplosis sorghicola) and head bugs (Calocoris
angustatus and Eurystylus oldi) in sorghum; stem borer (Coniesta ignefusalis) and head miner (Heliocheilus albipunctella) in pearl millet; pod borer
(Helicoverpa armigera) in chickpea and pigeonpea; and leaf miner (Apraorema modicella) and tobacco caterpillar (Spodoptera litura) in groundnut are the
most important pests of cereals and grain legumes in the semi-arid tropics (SAT).
Insect pests cause an estimated loss of over US$10 billion annually in the SAT. Since insecticide application is uneconomic under subsistence farming, it is
important to develop cultivars with resistance to insects. To achieve these objectives, we have standardized several techniques to screen and select for
resistance to insect pests in ICRISAT mandate crops.
Infester row technique to
screen for resistance to
sorghum midge.
A B
Cage technique to screen for resistance to shoot fly (A), midge (B), and
head bugs (C) in sorghum; and no-choice cage (D) techniques to screen
for resistance to Helicoverpa and Spodoptera in chickpea, pigeonpea and
groundnut.
These resistance screening techniques are being used to evaluate
germplasm, segregating breeding lines, mapping populations, and
transgenic plants for resistance to insect pests world wide.
C D
Detached leaf assay to screen for resistance to Helicoverpa and
Spodoptera in chickpea, pigeonpea, cotton and groundnut.
A B
Interlard fishmeal technique to screen for resistance to shoot fly. Artificial infestation technique to screen for resistance to stem borer.
Use of hot spot locations to screen for
resistance to Helicoverpa.
ICRISAT is a member of the CGIAR Consortium
HC Sharma, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Telangana, India. Email: h.sharma@cgiar.org