Mycelium ofAlternaria alternataas a potential biological control agent forEupatorium adenophorum

Abstract

The fungus, Alternaria alternata (Fr.) Keissler Strain 501, has been evaluated as a bioherbicide for control of Eupatorium adenophorum Spreng., but the biology of the pathogen Áhost interaction and the optimal environmental conditions for disease development and effective weed control are unknown. Disease development of A. alternata Strain 501 mycelia on E. adenophorum was assessed under several factors including pathogen inoculum concentration, plant age, dew period duration, post-dew temperature, storage temperature and duration. The minimum inoculum concentration required to kill E. adenophorum seedlings was 3.2 )/10 6 mycelial fragment mL (1 . E. adenophorum seedlings at the four-leaf-pair stage were more susceptible than the older plants, especially those at the older than seven-leaf-pair stage. With a dew period of at least 14 h, 100% mortality occurred. The optimal post-dew temperature for disease development was 18 Á258C. Storage at B/48C maintained the infectivity of A. alternata strain 501 mycelia on E. adenophorum longer. Using light and scanning electron microscopy to examine the infection process of A. alternata Strain 501 mycelia, it was shown that the time from initiation to completion of infection with mycelia was much shorter (14 h) than with conidia (72 h). It was further shown that mycelial infection occurred predominately through direct penetration at intercellular junctions, while conidial infection occurred predominately through stomatal penetration. This suggests that mycelia are more suitable as infection propagules for A. alternata strain 501 in a bioherbicide for the control of E. adenophorum .

Production and Stabilization of Mycoherbicides

“…Keissler/Eupatorium adenophorum Spreng. [44]. Possibly, in some cases the fungal mycelium is able to complete the infection process faster than conidia [44,45].…”

“…[44]. Possibly, in some cases the fungal mycelium is able to complete the infection process faster than conidia [44,45]. At the same time, the mycelium is generally less tolerant to the abiotic stress.…”

The Influence on Livestock Industry and Development Prospect of Eupatorium adenophorum Spreng

“…Another study showed that mycelia of Alterttaria alternate (Fr.) Keissler Strain 501 which separated from E. adenophorum were produce herbicides to slow down the invasion rate [27]. So far, there is no more effective method to control the growth and breeding about E. adenophorum.…”

Microbial Weed Control and Microbial Herbicides

“…Buch) in rice was increased by using conidia and chlamydospores (Cliquet & Zeeshan, 2008) and applying the biocontrol agent on juvenile rather than older starfruit (Jahromi, 2007). Qiang et al (2006) found that the mycelia of Alternaria alternata strain 501 were able to infect the host plant, Eupatorium adenophorum, in a much shorter time than with conidia. The Pseudomonas fluorescens strain D7 has the greatest efficacy on downy brome when the bacterium is applied in the fall.…”