Search

The efficacy of different nutrients (CaCl2, FeSO4, MgCl2, MgSO4, KCl, KNO3, NaCl, NaNO3 & ZnSO4) and fungicides (Bavistin, Kavach, Roko, Trifen, Blitox & Indofil M-45) against the mycelial growth and conidial germination of Alternaria alternata causing leaf blight disease of mulberry was assessed at 1000 and 2000 ppm concentrations. Results revealed that Ferrous sulphate and Blitox (Copper oxychloride 50% WP) at 1000 & 2000 ppm were found effective against A. alternata under in vitro conditions. They were further evaluated individually and in combination for their efficacy against Alternaria leaf blight under field conditions. It was observed that Ferrous sulphate @ 0.2% in two foliar sprays was most effective and reduced the disease severity to an extent of 85.62% besides increasing the leaf yield up to 23.04%, which was significantly higher than that of the recommended method (two foliar sprays of 0.2% Indofil M-45). The present study indicates that, ferrous sulphate @ 0.2% in two foliar sprays can be used for effective management of Alternaria leaf blight disease in mulberry. [ABSTRACT FROM AUTHOR]

The pre-penetration and infection process of Colletotrichum dematium on mulberry leaf was investigated by scanning electron microscope. Conidia produced on germination appressoria directly or at the end of short germ tubes. Appressoria were formed mostly over cuticle, but sometimes over stomata also. At 72 h post-inoculation, an extensive network of sub-cuticular runner hyphae (RH) was produced. The RH were traceable by the cuticular bulgings on leaf surface. The RH emerged to leaf surface through ruptured cuticle to form secondary infection hyphae (SIH). The SIH re-entered the leaf tissue by sending penetration branches through stomata. Conidia were formed singly on short conidiophores from the RH and SIH, at short intervals. The conidia developed on RH were exposed to leaf surface through ruptured cuticle. Some times conidia were released through stomata also. The RH and SIH had thick knots from which hyphal branches and conidia were developed. Definite acervuli were not developed. [ABSTRACT FROM AUTHOR]

In mulberry (Morus alba L.), various individual strains of plant growth-promoting rhizobacteria (PGPR) and synthetic analogs of naturally occurring plant activators have demonstrated their potential to elicit induced systemic resistance (ISR) against either brown leaf spot (Cercospora moricola) or leaf rust (Cerotelium fici) diseases. However, these biological and chemical elicitors have not been evaluated so far against multiple infections of both these diseases which commonly occur during the post-rainy season. The present study was therefore aimed to assess the capability of PGPR strains and chemical plant activators, as individual and in integration, in elicitation of ISR against multiple infections. Three PGPR strains, Azotobacter chroococcum strain Azc-3, Bacillus megaterium strain Bm-1 and Pseudomonas fluorescens strain Psf-4, and plant activators, acetyl-salicylic acid (ASA), sodium salicylate (NaS) and 4-amino-n-butyric acid (ABA) were selected for the study. Under in vitro tests, all the plant activators up to 2000 ppm concentration exhibited their compatibility with the PGPR strains tested. Upon assaying of elicitors with plant-pathosystem, disease suppression was significantly (p = 0.05) high with integrated application of PGPR strains and plant activators when compared to their individual applications. All the elicitors at individual application varied in their response to multiple infections with the plant age. However, integration of Azc-3 + ASA provided greater suppression to multiple infections of brown leaf spot and leaf rust diseases during the entire growth period of mulberry plants. Thus, this combination of biological and chemical elicitors holds great promise to provide an effective ecofriendly alternative to the toxic chemical fungicides presently recommended for the control of brown leaf spot and leaf rust diseases in mulberry. [ABSTRACT FROM AUTHOR]