Eriophyid mite Floracarus perrepae readily colonizes recovering invasive vine Lygodium microphyllum following herbicide treatment

Authors: David, Aaron; GLUECKERT, JONATHAN - University Of Florida; ENLOE, STEPHEN - University Of Florida; Carmona, Andrea; ABDEL-KADER, ANWAR - Former ARS Employee; Lake, Ellen

Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2021
Publication Date: 4/7/2021
Citation: David, A.S., Glueckert, J.S., Enloe, S.F., Carmona Cortes, A., Abdel-Kader, A.A., Lake, E.C. 2021. Eriophyid mite Floracarus perrepae readily colonizes recovering invasive vine Lygodium microphyllum following herbicide treatment. Biocontrol. 66:573-584. https://doi.org/10.1007/s10526-021-10087-6.
DOI: https://doi.org/10.1007/s10526-021-10087-6

Interpretive Summary: Lygodium microphyllum (Old World climbing fern) is among the most damaging invasive plant species in Florida, USA. Herbicide treatment can reduce cover of the plant temporarily, but the plant recovers within 1-2 years. A classical biocontrol agent, the gall-inducing mite Floracarus perrepae, could attack recovering L. microphyllum, thereby reducing the need for repeated treatments. We conducted two experiments to investigate the natural colonization of F. perrepae on post-treatment L. microphyllum. In the first experiment, we assigned tree islands to herbicide treatments, and found that 24 mo post-treatment, mite galls were abundant on treated islands and rare on untreated islands. In the second experiment, we investigated the separate effects of clipping and herbicide treatment on F. perrepae colonization within small-scale plots at 4 heavily invaded sites. Galls were most prevalent following cutting and least prevalent following herbicide 7 mo post-treatment. Taken together, we report that recovering L. microphyllum is susceptible to colonization by F. perrepae, and that biological control of L. microphyllum is compatible with these other management tactics.

Technical Abstract: Lygodium microphyllum (Cav.) R. Br. (Schizaeales: Lygodiaceae) is among the most damaging invasive plant species in Florida, USA. Following mechanical and herbicide treatment, the plant typically recovers to pre-treatment levels within 1-2 years through regrowth from the adult rhizome and recruitment of new sporelings. A classical biocontrol agent, the gall-inducing mite Floracarus perrepae Knihinicki & Boczek (Acariformes: Eriophyidae), could attack recovering L. microphyllum, thereby reducing the need for repeated treatments. Here, we investigated natural F. perrepae colonization of recovering L. microphyllum following treatment using two field experiments. First, we monitored F. perrepae colonization on adult regrowth and sporelings on tree islands that were clipped and treated with herbicide (glyphosate or triclopyr). At 24 mo post-treatment, mite galls were most abundant on glyphosate treated islands where >50% of adult rachises and >80% of sporelings exhibited galls and were rare on untreated islands. Second, we investigated the separate effects of clipping and herbicide treatment (triclopyr) on F. perrepae colonization within small-scale plots at 4 heavily invaded sites. Galls were most prevalent following cutting and least prevalent following herbicide 7 mo post-treatment. Taken together, we report that both L. microphyllum regrowth and especially sporelings were susceptible to colonization by F. perrepae, which can preferentially attack these plants compared to untreated plants. Our findings suggest that biological control of L. microphyllum is compatible with herbicide treatment, and future research is needed to determine how best to integrate these management tactics.