Gall Formation in Crofton Weed, Eupatorium adenophorum Spreng (syn Ageratina adenophora), by the Eupatorium Gall Fly Procecidochares utilis Stone (Diptera, Trypetidae)

Abstract

Procecidochares utilis lays eggs on the stem apex of Eupatoriurn adenophorurn and on hatching the larvae tunnel into the stem. In response to the presence of the larvae a gall forms in the stem which may contain from 1 to 23 larvae. Callus tissue differentiates and divides to block the entry passages and seal the larvae in the stem. The normal development of the stem is halted and it swells as the pith cells continue to divide and become gall parenchyma. A layer of highly meristematic nutritive tissue develops around the larval cavity on which the growing larvae feed. New vascular tissue differentiates in the pith region of the gall around the larval cavity. Growth of the gall ceases when the larvae pupate, by which time most of the nutritive tissue has been consumed and the cells in the pith region have enlarged. Just prior to pupation the mature larva cuts a cylindrical tunnel to the edge of the gall, leaving only the epidermis intact; it then returns to the central cavity to pupate. The adult fly escapes by breaking through the epidermal 'window' at the end of the cylindrical tunnel.

Gall-Inducing Tephritid Flies (Diptera: Tephritidae): Evolution and Host–Plant Relations

“…Their larvae breed in Archibaccharis, Chrysothamnus, Conyza, Corethrogyne, Ericameria, Erigeron, Grindelia, Heterotheca, Solidago (Astereae), Ageratina, Brickellia (Eupatorieae), Ambrosia, Bahiopsis, Helianthus (Heliantheae), and a few other genera of these tribes, although some records need verification (Foote et al, 1993;Norrbom et al, 2010). The biology of P. utilis Stone 1947, used as a biocontrol agent of Ageratina adenophora, has been described in detail (Dodd, 1953;Bess and Haramoto, 1958;Haseler, 1965;Bennett and van Staden, 1986;Freidberg and Mansell, 1995). Some Procecidochares species have multiple reported host plants, but most, if not all, induce stem or rosette galls usually in the plants of the same genus or tribe.…”

Sustainable management based on biological control and ecological restoration of an alien invasive weed, Ageratina adenophora (Asteraceae) in China.

“…It lays eggs on the stem apex and on hatching the larvae tunnel into the stem. In response to larvae presence, a gall forms in the stem, which may contain from 1 to 23 larvae (Bennett and Van Staden, 1986). Galls have been shown to cause severe stunting, a reduction in flowering and seed set and may result in ultimate death of the plant when they occurred in large numbers (Bennett and Van Staden, 1986).…”

“…In response to larvae presence, a gall forms in the stem, which may contain from 1 to 23 larvae (Bennett and Van Staden, 1986). Galls have been shown to cause severe stunting, a reduction in flowering and seed set and may result in ultimate death of the plant when they occurred in large numbers (Bennett and Van Staden, 1986). In 1984, P. utilis was introduced from Nienamu county Tibet into Kunming, Yunnan Province, for the control of crofton weed (Wei et al, 1989).…”

De novo transcriptomic analysis of the alimentary tract of the tephritid gall fly, Procecidochares utilis

“…When the eggs hatch, the larvae bore into the tender stems of E . adenophorum , where they feed and stimulate gall formation and enlargement, resulting in the blockage of growth and decreased nutrient transport [ 16 – 18 ]. Thus, P .…”

“…Although E . adenophorum can still grow with parasites, it’s the seed yield, plant height, branch number, photosynthetic capability, biomass accumulation, and distribution are all suppressed to affect its total growth [ 16 , 19 ]. Investigations of P .…”