Evaluation of host-specificity of Zygogramma bicolorata Pallister (Coleoptra: Chrysomelidae) for the biological control of Parthenium hysterophorus L. (Asteraceae: Heliantheae) in Nepal

Abstract

Host-specificity test of Zygogramma bicolorata Pallister (Coleoptra: Chrysomelidae) was conducted in the field and laboratory of National Entomology Research Center, Khumaltar, Lalitpur, Nepal during April to September, 2017. Multiple-choice and no-choice tests were conducted on Agerataum houstoniamum Mill., Bidens pilosa L., Chrysanthemum indicum L., Dahlia pinnata Cav, Guizotia abyssinica L., Helianthus annuus L., Lactuca sativa L., Parthenium hysterophorus L., Perilla frutescence L., Xanthium strumarium L., Zinnia elegans Jacq. and Jasminum officinale L. Among tested plant species, P. hysterophorus was only a preferred host of Z. bicolorata on which both larvae and adults fed. Ovipostion, larval development, pupation and adult emergence of Z. bicolorata occurred successfully on P. hysterophorus completing its life cycle. Larvae consumed H. anuus but could not pupate, and adults fed on it when starved for 5 days in no-choice test. Both adults and larvae of Z. bicolorata consumed X. strumarium and completed larval and pupal developments, but adults did not oviposit. Adult longevity was significantly reduced after feeding on H. annus (19.00 days) and X. strumarium (29.33 days) compared to P. hysterophorus (83.33 days).

Phytochemical-Based Evidence of the Health Benefits of Bidens Pilosa Extracts and Cytotoxicity

“…The no-choice test conducted by Mersie et al ( 2019) [17] on Asteraceae weeds revealed that Parthenium beetle (also Mexican beetle) (Zygogramma bicolorata) avoids laying eggs on B. pilosa as much as they could and also does not feed on it [17]. In a two-day multiple-choice test carried out by Bajracharya et al (2020) [18], Z. bicolorata avoided a few Asteraceae weeds including B. pilosa except Parthenium hysterophorus L. The extracts of B. pilosa significantly reduced the numbers of the Japanese pine sawyer (Monochamus alternatus) as well as the pine-wood nematode (Bursaphelenchus xylophilus) [19]. Due to the allelopathic characteristics of B. pilosa [6], the water extracts of the plant integrated with water irrigation have been found to effectively suppress weeds in a direct-seeded rice production system, which increases rice yield [20].…”