Arthropod-Plant Interactions (2021) 15, 265-271

Lulama G. Madire, David O. Simelane and Terence Olckers (2021)
Competitive interactions between the root-feeding Heikertingerella sp. and foliage-feeding Mada polluta on the invasive Tecoma stans
Arthropod-Plant Interactions 15 (2), 265-271
Abstract: Despite potential negative interactions between biological control agents, the release of multiple agents against invasive alien weeds is often justified. The leaf-feeding beetle Mada polluta Mulsant (Coleoptera: Coccinellidae), released against Tecoma stans (L.) Juss ex Kunth var. stans in South Africa, has so far been unable to contain the weed. Consequently, the root-feeding flea beetle Heikertingerella sp. (Coleoptera: Galerucinae) was introduced to complement M. polluta. The effects of the interaction between the two beetles on their performance and on the target weed were studied on potted T. stans plants in a quarantine glasshouse to assess whether they were additive, synergistic or negative. There was no significant difference in the percentage survival of the P1 adults of either beetle when tested alone or in combination. Mada polluta produced significantly more F1 adult progeny than Heikertingerella sp. when tested alone, while both beetles produced significantly fewer offspring when tested in combination. Leaf damage by M. polluta alone was higher than that caused by Heikertingerella sp. alone, but in combination was not significantly higher than damage by M. polluta alone. Although both beetles on their own caused a significant reduction in leaf density relative to the control, leaf density was significantly lower when in combination. Despite significant reductions in plant height relative to the control, the differences between the three beetle treatments were not significant. Although competitive interactions caused a trade-off between agent proliferation and their impact on the growth of T. stans, these data need to be confirmed in the field.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): David O. Simelane

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
classical biocontrol/new introduction

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tecoma stans (weed)		South Africa
Mada polluta (weed bioagent)	Tecoma stans (weed)		South Africa