Bakkiya-PAT.pptxpresentation to download Agroforestry.pptx

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Agroforestry.pptx

1. Diseases of crossandra

2. Major Diseases Wilt : Fusarium solani .
Stem rot : Rhizoctonia solani .
Leaf blight : Colletotrichum crossandrae .
Alternaria leaf spot : Alternaria amaranthi var. crossandrae

3. Wilt : Fusarium solani Wilt is observed in patches. In the field the disease is observed one month after transplanting.
Leaves of infected plants become pale and droop.
Margin of the leaves show pinkish brown discolouration.
The discoloration spreads to the midrib in a period of 7 to 10 days.
Stem portion gets shriveled. Dark lesions are noticed on the roots extending upto collar region which result in sloughing off the cortical tissue.
Favoured by nematodes.

4. Pathogen Fungus produce 3types of spores A.Micro conidia – Ovate, 1-2 celled, hyaline B.Macro conidia Spindle shape, 3-5 septate hyaline, curved ends C.Chlamydospores Thick walls are terminal or intercalary Mode of spread Primary – Chlamydospores survive in soil
Secondary – Water-borne conidia

5. Management Affected plants - pulled out and destroyed Soil application of Phorate at the rate of 1 g/plant on 10th day of transplanting. Soil drenching with Carbendazim 0.1 per cent or Copper oxychloride 0.25 per cent on 30 days interval controls the disease The treatment may be repeated after 3 to 4 weeks if needed.

6. Stem rot : Rhizoctonia solani Symptoms The pathogen also causes pre-emergence damping off,
Brown to black lesions develop on stem just above soil level and result in girdling of the stem.
The lesions extend to the upper part of the stem and result in collapse of seedlings
The roots are also rotted.

7. Pathogen Mycelium is septate Sclerotia - irregular brown to black. It produce terminal and intercalary

Mode of spread

Primary Through sclerotia (thick outer layer) Secondary – Through wind borne basidiospores Favourable conditions
Soil PH above 5.8
Temperature -15°c – 35°c, Dry soil

8. Management Drenching with Fosesty1-A1 has been found effective in the control of the disease.

Spray carbendazim1g/l, Benzomy land Iprodione

9. Leaf blight: Colletotrichum crossandrae Symptoms leaves consist of the development of brownish, depressed necrotic areas surrounded by reddish and slightly raised margins. Initially the spots appear as brownish specks but become darker as they expand. The lesions are more prominent on lower leaves and confined to the margins. Infected leaves roll up, shrivel and drop off, leaving a barren stem with a whorl of young leaves at the top.

10. Pathogen Mycelium is septate, intercellular as well as intracellular
Acervuli are round and elongated in shape
Conidiophores are simple, hyaline, cylindrical, aseptate.
Conidia hyaline, one celled, uninucleate,

11. Mode of pathogen Primary – Through Ascospore from dried fallen leaves. Secondary – Through wind-borne pathogen Favourable conditions Temperature 26°c
RH 100%

12. Management Collect and burn the infected plant debris. Spraying with Benomyl 0.1% (or) Mancozeb 0.2% (or) Carbendazim 0.1% .

13. Alternaria leaf spot : Alternaria amaranthi var . crossandrae Symptoms This disease was first reported from Tamil Nadu during 1972.
Infected leaves show small, circular or irregular yellow spots on the
upper surface.
They soon enlarge turn brown and develop dark brown concentric rings.
Infected leaves become yellow and drop off prematurely.

14. Pathogen Mycelium’s septate, branched, light brown hyphae
Conidia are muriform , 5 to 10 transverse and a few longitudinal septa are present in each conidium . Mode of spread Survive in the debris of diseased plants and can persist for 1to 2 years in the soil.
Primary-seed borne pathogen.
Secondary- infection through wind and water.

15. Management Collect and destroy the infected plant debris
Follow at least 2 years crop rotation.
Use healthy seed and treat them with captan (0.3%).
Avoid moisture and stagnant conditions.
Spraying with Benomyl 0.1% (or) Mancozeb 0.2%