The rice leaffolder, Cnaphalocrosis medinalis Güenée (Lepidoptera: Crambidae), has emerged as a serious pest with significant outbreaks over the last decade in several rice‐growing countries, including China and Bangladesh and resulting in heavy rice yield losses. Climate changes (particularly high temperatures in late winter in Bangladesh) coincide with upsurge in outbreaks of this pest. We generated a statistical model using more than two decades of data to show that increased temperatures associate with this upsurge. Over the 22‐year model period, leaffolder populations in November increased significantly, corresponding to significant monthly temperature trends (but not rainfall) over the same period. Utilizing a linear model, we find that increasing temperature interacts with the amount of rainfall. With the variable month as a proxy for all seasonal effects affecting leaffolder abundance, the model reveals a significant correspondence with climate variations compared to average conditions; specifically, the model predicts that increasing maximum temperatures will lead to more leaffolder, while more rain will decrease their abundance. This study suggests that warmer environment contributed to recent outbreaks of leaffolder in rice‐growing countries; thus, climate change increases rice yield losses by increasing pest population in the field.

Designing breeding programs for rapeseed (Brassica napus L.) cultivars with developed seed and oil yields needs information about the genetic variability of characters. In this study, 40 rapeseed genotypes were evaluated for genetic variation and relationships between 12 agro-morphological characters. Brassica species represent a broad range of crops. This redirects the high degree of genetic diversity and allied phenotypic plasticity. Significant differences among the clusters were observed. The first two components with Eigen value were greater than unity contributed a total of 42.77% variation to the divergence. The genotypes were grouped into five clusters. Cluster V contained the maximum number of genotypes (11) and cluster III contained the lowest (4). The highest inter-cluster distance was found between cluster II and cluster V and the lowest between cluster II and cluster IV. The highest intra-cluster distance was noticed for cluster I and the lowest for cluster V. Considering diversity pattern and other agronomic performance lines Nap-0837, Nap-0733-1, Nap-2066, Nap-9901, Nap-108 and BARI-8 could be considered apposite parents. This information is suitable for hybrid breeding and encouraging breeders to exchange their germplasm as to enlarge the genetic diversity of breeding accessions.

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