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 obtusa Clavigralla 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 2014 ICRISAT is a member of the CGIAR Consortium

Ceroplastodes cajani infested pigeonpea.