Population dynamics of potential bioagents of mustard aphid, Lipaphiserysimi(Kaltenbach) on different cultivars of rapeseed-mustard

Abstract

Field experiment was conducted to study the population dynamics of potential bioagents of mustard aphids on 9 different cultivars which included: Brassica alba cv. PSB-I, Eruca sativa Mill cv. T-27, Brassica campestriscv. BSH-I, Brassica napuscv. Sheetal, B. carinataBraun cv. CCN-06- 1, B. junceaL. cv. Varuna, B. nigraKoch. cv. PBR-I, Brassica campestriscv.YST-151 and Brassica campestriscv. PT-30. Population of aphid and natural enemies was recorded at weekly intervals. The results indicated that the first appearance of coccinellids and syrphids has been observed during 4th standard week, which gradually build up population and attained peak during 9th (pooled mean 1.42 coccinellids/ plant and 0.122 syrphid larva/plant) and 8th standard week (pooled mean 3.96 coccinellids/plant and 0.228 syrphid larva/plant) in 2008-09 and 2009-10 respectively, followed by a declining trend in the following weeks. Similarly first appearance of parasi-tization has been found to occur from 4th standard week followed by a gradual increase in the following weeks with maximum parasitization on PT-30 (33.32%) and BSH-1 (35.25%) during 2008-09 and 2009-10 respectively. Correlation between abiotic factors and these natural enemies was also studied. It has been observed that with the increase of aphid population the population of natural enemies also increased. The population dynamics of mustard aphids and its natural enemies var-ied according to climatic situations and between host plant species. So by computing population trends of both natu-ral enemies and aphids with meterological records would generate information on relative abundance and would certainly help in formulating sound pest management strategies against mustard aphid.

Population Dynamics of Mustard Aphid <i>Lipaphis erysimi</i> (Kalt) and its Coccinellid Predators

“…The coccinellid predators C. sexmaculata (L), C. septempunctata (F) and C. transversalis (F) preying on L. erysimi, corresponding with the peak aphid incidence; a substantial positive association (r= 0.74, 0.82) was found between aphids and coccinellid predators. These results agree with those of Singh and Lokeshwari's (2010), Singh et al (2017) and Varshney et al (2017).…”

Population Dynamics of Mustard Aphid <i>Lipaphis erysimi</i> (Kaltenbach) and its Natural Enemies

“…1, 2). These findings corroborate with those of Singh and Lokeshwari (2010), Singh et al (2017) and Varshney et al (2017).…”

Influence of Silicic Acid Foliar Spray on the Incidence of Sucking Insect Pests and their Natural Enemies in Rapeseed

“…To record the occurence of C. transversalis, ten plants were randomly selected in each plot and the number of grubs and beetle(s)/ plant was recorded (Sarwar, 2013). In the case of syrphid (E. balteatus), ten plants were randomly selected in each plot and the number of larva/ plant was recorded (Varshney et al, 2017). After 80 DAS, five plants were randomly collected from each replication and analyzed the Si content at the Department of Environmental Sciences, Tezpur University, Tezpur.…”