The sunflower lace bug, Galeatus scrophicus: morphology, spatial distribution pattern of nymphs and its damage on sunflower and chrysanthemum
2021
Yazdanian, Mohsen | Hosseini Mighani, Atefeh
Abstract The sunflower lace bug Galeatus scrophicus has yet been recorded in Iran on tamarisk, sunflower and chrysanthemum. In the present study, its morphology, spatial distribution pattern of nymphs and symptoms of damage were investigated. The insect has five instars and average body length in first to fifth instars and male and female adults were 0.54 ± 0.03, 0.76 ± 0.06, 1.01 ± 0.06, 1.23 ± 0.07, 1.76 ± 0.05, 2.72 ± 0.11 and 2.98 ± 0.10 mm, respectively. Nymphs have thorn-like structures on their bodies which become longer by introducing to the next instar. At fifth instars, bulb-like structures similar to those of adults appear on body. Larger size of hood in comparison to the posterior pronotal bulb and five cells in paranotal process are two characters of adults of this species. Average body length in male and female adults were 2.72 ± 0.11 and 2.98 ± 0.10 mm, respectively. On sunflower and chrysanthemum, nymphs and adults caused damage just on upper and lower leaf surfaces (on sunflower also on upper and lower surfaces of involucral bracts). Damage on both upper and lower surfaces began mainly at leaf margin (sometimes at the adjacent of midrib) and then extended to the inner parts of lamina. Faeces of nymphs and adults were visible individually and at high numbers at feeding sites as shiny small black spots. According to the results, the spatial distribution of nymphs on sunflower by using five distribution indices was random. For determination of spatial distribution parameters, Taylor's model was more adequate than Iwao's model.
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