Etiology and disease cycle

Rice crop accounts for nearly a third of the total area under food grains in India and is the staple food for a significant portion of the world‟s population. Widely varying factors influence the growth of rice in different rice growing areas and render the crop susceptible to various pathogenic and non-pathogenic diseases, resulting in extensive damage of grain and straw yield. Bacterial leaf blight disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is a serious menace to rice production in India, besides other rice producing countries.

16p angicungduoc6 22-07-2020 32 1   Download

In recent years, twister disease of onion has become epidemic in coastal tract and other onion growing districts of Karnataka which caused heavy loss. Survey carried out during kharif and rabi/summer 2011-12 and 2012-13 revealed typical symptoms of the disease twisting of leaf, neck with blight as well as dieback (anthracnose), scanty root system with galls and showing fungal growth was noticed. Artificial inoculations of onion seedlings with Colletotrichum gloeosporioides, Fusarium oxysporum, Meloidogyne spp. alone and in combinations expressed twister disease symptoms.

14p nguaconbaynhay6 23-06-2020 14 0   Download

Scab is the most serious disease of apple, particularly in years with cool wet springs and summers. Symptoms occur on leaf blade, fruit, petioles, sepals, blossoms, young shoots, and bud scales. The lesion increase in size as olive green colored which become progressively darker brown raised and velvety in appearance due to the abundant production of conidiophores and conidia.

12p gaocaolon5 14-06-2020 6 1   Download

The progression of disease in localized osteomyelitis is characterized by a cycle of microbial invasion, vascular disruption, necrosis and sequestration. The host inflammatory response, discussed in detail below, results in obstruction of small vessels due to coagulopathy and oedema. As a result of this, cortical bone undergoes necrosis and is detached from surrounding live bone, creating an area known as a sequestrum. This provides a fertile environment for further bacterial invasion and progression continues.

188p wqwqwqwqwq 20-07-2012 75 8   Download