Diseases and Management of Crops under Protected Cultivation
Diseases and Management of Crops under Protected Cultivation
Diseases and Management of Crops under Protected Cultivation
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(<strong>Diseases</strong> <strong>and</strong> <strong>Management</strong> <strong>of</strong> <strong>Crops</strong> <strong>under</strong> <strong>Protected</strong> <strong>Cultivation</strong>)<br />
Fig. 1. Classification <strong>and</strong> geographic origins <strong>of</strong> R. solanacearum strains based on sequence<br />
analysis <strong>of</strong> endoglucanase is a type <strong>of</strong> cellulose, which is class <strong>of</strong> enzymes produced by<br />
fungi, bacteria <strong>and</strong> protozoans that catalyze the cellulolysis <strong>of</strong> endoglucanase gene<br />
sequences. Numbers indicate sequevars (1 to 23) (Source : Fegan <strong>and</strong> Prior, 2005)<br />
Table 1. Characteristics <strong>of</strong> races <strong>and</strong> their relationship to other subdivisions <strong>of</strong> Ralstonia<br />
solanacearum.<br />
Race Host range Geographical distribution Biovar RFLP Division<br />
1 Wide Asia , Australia, Americas 3, 4<br />
I<br />
1<br />
II<br />
2 Banana other Caribbean, Brazil, Philippines 1 II<br />
Musa spp.<br />
3 Primarily Worldwide 2 II<br />
potato<br />
4 Ginger Asia 3, 4 I<br />
5 Mulberry China 5 I<br />
Diagnosis <strong>of</strong> Bacterial wilt<br />
1) Disease symptoms<br />
Potato<br />
Foliage symptoms include rapid wilting <strong>of</strong> leaves <strong>and</strong> stems usually first visible at the<br />
warmest time <strong>of</strong> day. Eventually, plants fail to recover, become yellow <strong>and</strong> brown necrotic <strong>and</strong> die.<br />
As the disease develops, a streaky brown discoloration <strong>of</strong> the stem may be observed on stems<br />
above the soil line. The leaves may have a bronze tint. Epinasty <strong>of</strong> the petioles may occur. A<br />
white, slimy mass <strong>of</strong> bacteria exudes from vascular bundles, when broken or cut. This slime oozes<br />
spontaneously from the cut surface <strong>of</strong> a potato stem in the form <strong>of</strong> threads, when suspended in<br />
water. Under cool growing conditions, wilting <strong>and</strong> other foliar symptoms may not occur. On tubers,<br />
external symptoms may or may not be visible, depending on the state <strong>of</strong> development <strong>of</strong> the<br />
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