Bidens pilosa Extract Effects on Pine Wilt: Causal Agents and Their Natural Enemies

Abstract

We investigated the nematicidal and insecticidal activities of the aqueous extract from Bidens pilosa var. radiata on pine-wood nematode (Bursaphelenchus xylophilus) and Japanese pine sawyer (Monochamus alternatus) larvae and adults, the causal agent and vector of pine wilt, respectively. The aqueous extract killed the pine-wood nematode, adults, and larvae of the vector in vitro at all concentrations tested, and the effect decreased significantly with increasing extract dilution. Repellent activity was observed on the nematode and the vector adults as well, although the activity decreased with time in case of the vector. Furthermore, the aqueous extract of B. pilosa effectively promoted approximately 3.0–9.0 mm of hyphal growth in Beauveria spp., when compared with the control treatment. A minor insecticidal effect was also observed on two species of click beetle (Cryptalaus larvatus pini and Paracalais berus), which are natural predators of the Japanese pine-sawyer larvae. Pesticidal and repellent activities of the aqueous extract observed on several organisms related to pine wilt suggest that a multifactorial approach may effectively control this devastating disease.

Identification of Repellents from Four Non-Host Asteraceae Plants for the Root Knot Nematode, Meloidogyne incognita

“…radiata significantly suppressed M. incognita and the pine-wood nematode populations in semi-field trials . These reports and the findings from the current study show that the different plant parts contain bioactive metabolites that disrupt nematode life processes.…”

“…For Amaryllidaceae, allicin and polysulfides identified from Allium species have been used in the field to manage RKNs . For Asteraceae plants, α-terthienyl from Mexican marigold Tagetes spp ,, and leaf extracts from Bidens pilosa were used as nematicides for RKNs, , while the essential oils from flower heads of Chrysanthemum coronarium, Chrysanthemum segetum, Calendula officinali, Calendula suffruticosa subsp. algarbiensis, and Calendula maritima were found to significantly reduce egg hatchability and J2 viability of Meloidogyne artelia .…”

Chemo-Ecological Insights into the Use of the Non-Host Plant Vegetable Black-Jack to Protect Two Susceptible Solanaceous Crops from Root-Knot Nematode Parasitism

“…Several studies have evaluated the nematicidal activity of extracts from above-ground tissue of B. pilosa applied in different formulations against various plant parasitic nematodes. ,,, For instance, aqueous and ethanolic extracts of B. pilosa variety “radiata” caused significant immobilization, mortality, repellency, and egg hatching inhibition of M.…”

“…incognita . Additionally, boiled aqueous extracts showed a concentration-dependent nematicidal activity against the pinewood nematode and root-knot nematodes , without adverse effects on beneficial free-living microorganisms.…”

“…Cultural methods such as crop rotation, dead-end trap crops, and processed plant products are commonly used by smallholder farmers. For example, plant parts and extracts of the Asteraceae family have been found to reduce populations of PPNs via different modes of action. ,, These include the Mexican marigold T. minuta (Asteraceae), which is used as a cover crop as it produces phytochemicals that are toxic to PPNs.…”