Pests are the key yield limiting factors in agricultural production systems around the world. Their
population dynamics are shown to vary with the modifications in agro-ecosystem, cropping system and
management practices. Plentiful information is available on assessment of their seasonal population
fluctuations mainly due to abiotic factors in conventional tillage (CT) based cereal production systems.
However, while transitioning from CT based production systems to a more stable and ecologically
sustainable conservation agriculture (CA)- based systems, the pest dynamics particularly in relation to
biotic factors are not clearly understood. Therefore, we conducted a systematic study on pest dynamics
under long-term CA in major cropping systems of North-West Indo-Gangetic plains. In our study, crop
rotations, no-tillage and residue retention led to more diverse aerial and epigeic arthropod communities
which seemingly increased biological control of pests through predation by natural enemies, that
subsequently resulted in no significant increase of pests in the CA-based cereal systems. CA-based ricewheat
(RW) system had the highest insect diversity than respective CT system and maize-wheat (MW)
systems. In RW system, stem borers (+7.0% and -11.2%), leaf folders (15.6% and 4.8%), leafhoppers
(-2.9% and -3.6%) and grain sucking insects (0% and -2.0%) were observed at tillering and grain filling
stage, respectively under CA- based system compared to CT- system. Similarly, in MW system, stem
and silk borers (-14.8% and -14.0%), defoliators (-4.6% and -36.8%), beetles (-22.9% and -4.2%), shoot
fly (-9.2% and 0%) were recorded. The parasitoids and predators density under CA-based RW system
was about 20 folds at tillering stage and 3.5 folds at grain filling stage, while, under CA-based MW
system it was 6.4 times (at tillering stage) and 3.9 times (at grain filling stage) as compared to their CT
counterparts. The increased density of both aerial and epigeic beneficial arthropod diversity perhaps
yields in increased niche differentiation and consequently reduced herbivory in CA systems. The CA
systems naturally conserve and foster beneficial biodiversity that potentially helps mitigating the
populations of several detrimental arthropods by making production systems more amenable to
biocontrol.
