Mustard Stem Rot Busters Quiz

Explore practical knowledge and approaches for managing stem rot in mustard crops. This quiz covers symptoms, disease cycles, prevention, and integrated management strategies relevant to mustard stem rot.

1. Identifying Stem Rot in Mustard

   What is the most characteristic symptom of stem rot (caused by Sclerotinia sclerotiorum) observed in mustard fields?

   1. White cottony fungal growth on stems near soil surface
   2. Black blister spots on leaf veins
   3. Yellowing of leaf margins only
   4. Downward curling of seed pods

   Explanation: White cottony fungal growth on stems, especially near the soil, is a distinguishing sign of Sclerotinia stem rot. Yellowing of leaf margins is symptomatic of leaf blight or nutrient deficiency, not stem rot. Pod curling is unrelated and more typical with insect issues, while black blisters on leaf veins are typical of some viral infections, not Sclerotinia.

2. Disease Favorable Conditions in Mustard Fields

   Which environmental condition most favors the development and spread of stem rot in mustard crops?

   1. Temperatures below freezing for weeks
   2. Soil with low organic matter and high salinity
   3. Hot, dry weather and direct sun exposure
   4. Prolonged high humidity with mild temperatures

   Explanation: Sclerotinia stem rot thrives in prolonged high humidity and moderate temperatures, which help spores germinate and infect. Hot, dry weather restricts fungal growth. Low organic matter or high salinity affects overall plant health, not specifically Sclerotinia. Prolonged freezing suppresses fungal activity rather than promoting disease.

3. Preventing Initial Infection

   Which of the following is an effective cultural method to reduce stem rot risk in mustard crops?

   1. Practicing crop rotation with non-host crops
   2. Delaying harvest beyond full ripeness
   3. Increasing nitrogen fertilizer rates
   4. Planting mustard seeds deeper than usual

   Explanation: Crop rotation with non-host crops lowers leftover fungal inoculum in the soil, effectively reducing disease risk. Excess nitrogen can promote lush growth, increasing susceptibility. Planting seeds deeper or delaying harvest does not prevent infection and may introduce other risks unrelated to stem rot.

4. Integrated Disease Management

   In an Integrated Disease Management (IDM) strategy for mustard stem rot, which practice is most important to combine with fungicide application?

   1. Removing infected plant residues after harvest
   2. Using overhead irrigation
   3. Early sowing after the rainy season
   4. Spraying insecticides at flowering

   Explanation: Removing infected residues reduces survival and spread of Sclerotinia. Overhead irrigation increases disease risk by raising humidity near plants. Early sowing may help, but only if combined with other practices. Insecticides target insects, not Sclerotinia, and are not part of IDM for this disease.

5. Chemical Control Timing

   At what growth stage should fungicides be applied to best control stem rot in mustard according to standard recommendations?

   1. Just before harvest
   2. During seedling emergence
   3. At early flowering stage
   4. After full pod formation

   Explanation: Applying fungicide at early flowering is most effective because this is when infection typically occurs. Waiting for full pod formation or just before harvest is often too late. Seedling emergence is not usually a critical period for stem rot infection, so spraying then is ineffective.