Pigeonpea, Cajanus cajan is one of the most important grain legumes in India, East and southern Africa and the West Indies. In addition to changes in cropping patterns, climate change has resulted in emergence of serious pests such as spotted pod borer, Maruca vitrata, pod sucking bug,

1. Introduction
Pigeonpea, Cajanus cajan is one of the most important grain legumes in India, East
and southern Africa and the West Indies. In addition to changes in cropping patterns,
climate change has resulted in emergence of serious pests such as spotted pod borer,
Maruca vitrata, pod sucking bug, Clavigralla spp. and mealy bug, Drepanococcus
cajani (Kumar and Nath, 2005; Sharma, 2005). Heavy rains during October -
November often result in outbreaks of H. armigera and M. vitrata in southern India,
while early warming of weather in North India (3 – 5 ºC higher than the normal in
March) result in heavy H. armigera damage in pigeonpea and chickpea in North India
(Sharma, 2014).
Effect of climate change on incidence of insect pests in pigeonpea
HC Sharma, AR War, RS Munghate, M Pathania and T Nagaraja
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Telangana, India.
Fig. 1. Helicoverpa armigera incidence in relation to temperature and RH on different genotypes
of pigeonpea across planting dates under field conditions.
Conclusions
• Temperature and RH showed a considerable effect on insect incidence and arthropod
diversity across planting dates in pigeonpea.
• Incidence of M. vitrata declined in crops planted late in the season.
• There is a need to develop genotypes and cropping systems to reduce pest associated
losses in pigeonpea.
Maruca vitrata Melanagromyza obtusaClavigralla sp.Helicoverpa armigera
References
Kumar A and Nath P. 2005. Insect pests of early pigeon-pea in relation to weather
parameters. Annals of Plant Protection Sciences 13(1): 23-26.
Sharma HC. 2005. Heliothis/Helicoverpa management: Emerging Trends and Strategies
for Future Research. New Delhi, India: Oxford and IBBH Publishing Co. 469 pp.
Sharma HC. 2014. Climate change effects on insects: Implications for Crop Protection
and Food Security. Journal of Crop Improvement 28: 229-259.
For more information, please write to: Dr HC Sharma, Principal Scientist – Entomology, ICRISAT. Email: h.sharma@cgiar.org
Materials and Methods
• Five pigeonpea genotypes (ICPL 88039, ICPL 98008, ICPL 187-1, ICPL 332 WR
and ICPL 87) were grown for studying the effect of climate change on incidence
and severity of insect pests during the 2012/13 rainy season under field
conditions.
• The test material was sown at monthly intervals from June - Sept. Data were
recorded on numbers of insects/plant or pod damage at fortnightly intervals in
each planting.
• The abundance of insect pests was correlated with temperature and RH during the
observation period.
Results
• Insect abundance/damage differed significantly across planting dates, genotypes and
the observation periods.
• Egg/larval abundance of H. armigera and M. vitrata was maximum during Sep - Oct,
which corresponded to moderate temperatures (Tmax 29 ℃ and Tmin 21 ℃) and high
RH (RHmax 91% and RHmin 71%).
• There was a progressive decline in M. vitrata infestation in the subsequent plantings.
• Under very high incidence of pod borers during Sept - Oct, all the genotypes suffered
very heavy pod borer damage (Fig. 1).
ICPL 87 (Susceptible) ICPL 332WR (Resistant)
Thrips infested pigeonpea flower. Aphis craccivora infested pod.
July 2014ICRISAT is a member of the CGIAR Consortium
Ceroplastodes cajani infested pigeonpea.