Insect biodiversity on mix cropping of chilli and onion crops

The experiment was conducted during winter season 2015 on experimental field of Oil Seed Section, Agriculture Research Institute Tandojam. To determine the insect biodiversity on chilli (Cv. Ghotki) and onion (Cv. Sahzadi) mixed crop, the crop was cultivated on an area of ½ acre. The biodiversity of mix crop field was also compared with the biodiversity of chilli and onion fields cultivated separately. The plants were transplanted on ridges while in mix crop of onion and chilli, the plants were transplanted alternately on the same ridges. Sampling of insect species was done by in situ and sweep net methods from first week of October to last week of December 2015. For this purpose, 15 plants were randomly selected from the field of onion and chilli cultivated separately, while 15 plants of each onion and chilli were selected from mixed crop. The selected plants were thoroughly examined for the population of chewing insects while sucking insects were counted by examining 1 leaf per selected plant. Fifty strokes were also performed to collect flying insects in each field. To determine diversity, diversity maximum, species richness and evenness, Shannon diversity indices were used.Results showed that in mix crop, the total specimens 2565 were collected, which were belonging to 24 different species. Among them, 15 species were pests while 6 and 3 species were predators and pollinator, respectively. The highest diversity (H=1.204) was recorded in 2nd week of October while Hmax (H/=1.36) was recorded in 4th week of October. The maximum evenness (J/=0.91) and richness (D=1.36) were recorded in 1st week of December, respectively. The paired T-test showed that the population of aphid, onion leaf miner, thrip, mite and cutworm appears non-significantly on alone and mix cropping of onion and chilli.