The U.S. has seen an increase in introductions of invasive plant pests into agricultural crops. In Florida, one such invasive species is a bacterial plant pathogen that causes Asiatic citrus canker...

https://apsjournals.apsnet.org/doi/pdf/10.1094/PHP-2002-0812-01-RV

Citrus Canker: The Pathogen and Its Impact

Of all the agricultural pests and diseases that threaten citrus crops, citrus canker is one of the most devastating. The disease, caused by the bacterium Xanthomonas axonopodis pv. citri, occurs in large areas of the world's citrus growing countries including India. At least 3 distinct forms or types of citrus canker are recognized. Among these, Asiatic form (Canker A) is the most destructive and affects most of the major citrus cultivars. Severe infection of the disease produces a variety of effects including defoliation, dieback, severely blemished fruit, reduced fruit quality and premature fruit drop. Warm, humid, cloudy climate, along with heavy rainfall and strong wind promotes the disease. Control of canker in countries or regions where the disease is not present include quarantine or regulatory programme to prohibit introduction of infected citrus plant material and fruit, as well as continuous and strict surveying in the field and the immediate destruction of infected trees. In countries where canker is present, integrated systems of compatible cultural practices and phytosanitary measures consisting of resistant hosts, removal of inoculum sources, properly designed windbreak systems, timely application of protective copper-containing and/or antibiotic sprays are generally the most effective means of disease management. This paper reviews the current state of knowledge and understanding on pathogens and strains associated with the disease and their identification, host-pathogen interaction, molecular mechanism of pathogenicity , epidemiological aspects and management practices.

/pdf/citrus-canker-a-review-56v8urqr8i.pdf

Citrus canker - A review

Increasing realization of the ill effects of long sustained, exclusive use of chemical fertilizers, and consistent growing demand from the consumers for fruit quality, coupled with unsustainable productivity of citrus, have fostered experimentation with some alternative cultural practices. Organic culture is claimed to be the most benign alternative. Use of organic materials such as farmyard manure, cakes of plant origin, vermicompost, and microbial bio-fertilizers on one hand, and exploiting the synergism between citrus-vesicular arbuscular mycorrhizal fungus on the other hand, are important components of the bio-organic concept of citrus cultivation. Mycorrhizae were observed to be highly effective in low fertility, coarse textured soils. Mycorrhizal-treated trees had better plant growth and uptake of nutrients like P, Ca, Zn, Cu, and Fe compared to non-mycorrhizal trees. Inoculation of soil with mycorrhizae also helped in regulating the water relations and carbohydrate metabolism of citrus tre...

Organic Citrus: Soil Fertility and Plant Nutrition

Evaluation of the antibiotic activity of extracellular compounds produced by the Pseudomonas strain against the Xanthomonas citri pv. citri 306 strain

Species of Trichoderma are diverse fungal microbial community known and explored worldwide for their versatilities as biocontrol and growth promoting agents. They are also widely exploited in industries as sources of enzymes. A large number of research groups are working on various aspects of Trichoderma viz., diversity, ecology and their applications. In India, about 110 groups representing various universities and research institutes are working with about 15 different species and have published about 460 research papers. Trichoderma harzianum and Trichoderma viride are the widely used species and have been exploited on about 87 different crops and about 70 soilborne and 18 foliar pathogens, respectively. This review aims to give an overview of the status of usage of Trichoderma on important agricultural crops by different groups and organizations in the country.

http://epubs.icar.org.in/ejournal/index.php/IPPJ/article/download/39580/17829

Status of Trichoderma research in India: A review

Four species of bacteria (Bacillus subtilis, B. polymyxa, Pseudomonas fluorescens and Serratia marcescens) and 3 species of fungi (Aspergillus terreus, Trichoderma viride and Trichoderma harzianum) isolated from the phylloplane of lemon cv. Assam lemon, inhibited in vitro growth of Xanthomonas campestris pv. citri, the incitant of citrus canker. When the antagonists were tested for their efficacy in the control of citrus canker by applying them over crop foliage of Assam lemon, they also reduced citrus canker incidence under field conditions. B. subtilis was the most effective antagonist exhibiting max. (14.7 mm) inhibition of the pathogen and reducing the disease incidence by 61.9%.

http://epubs.icar.org.in/ejournal/index.php/IPPJ/article/download/20077/10232

L. C. Bora

Papers

Phylloplane microflora of citrus and their role in management of citrus canker.

Goat weed - a host of citrus canker (Xanthomonas campestris pv. citri).