diseases of aloe vera

diseases of aloe vera and their management

1. Diseases of aloevera COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 STUDENT Mr.YUVARAJ.S.C ID. No. 2015021143 COURSE TEACHER Dr. PARTHASARATHY S Asst. Professor (Plant Pathology)

2. DISEASES OF ALOEVERA Base rot – Pectobacterium chrysanthemi Leaf spot- Alternaria alternata Aloe rust – Phakopsora pachyrhizi Sooty mould - Complex disease Cladosporium , Aureobasidium , Antennariella , Limacinula , Scorias , and Capnodium . Basal stem rot – Fusarium spp Anthracnose – Colletotrichum gloeosporioides

3. BASE ROT Causal organism : Pectobacterium chrysanthemi Other name : Bacterial soft rot Host plant Potato, Sweet potato, Cassava, Onion, Cabbage, Carrot, Tomato, Beans, Cotton, Coffee, Banana.

4. SYMPTOMS An initial infection occurs on the outer petiole which is in contact with the soil and then progresses. An infected leaf is watery and often has a complete leaf rot. The affected area becomes soft and mushy and generally turn dark in colour . An infected leaves has a soft and watery decay. Infected leaves rots internally resulting in the wilting of young leaves which is then followed by tip collapse and dieback.

5. Pathogen Bacteria are non spore forming, motile, short rod shaped. Mode of spread Primary and secondary spread are through water borne bacteria.

6. FAVOURABLE CONDITIONS Infected plant debris left rotten in the field. Presence of onion maggot as the vector for soft rot in onion and garlic and root rot nematodes that causes lesions on the roots. Plant wounds and injuries. Hot and damp weather with plenty of rainfall trigger the disease to occur. Water is required for the bacteria to invade.

7. IDM There is no known effective control measure of bacterial soft rot. Proper land preparation to have a well drained soil. Control nematodes and other insect pests that serve as vectors of the bacteria to invade the plant tissues. Avoid plant injury during weeding.

8. Remove infected plants immediately. Practice crop rotation by using crops that are not susceptible to the bacterial soft rot disease like soybean, forage legumes.

9. LEAF SPOT Causal organism : Alternaria alternata Symptoms Small, circular to oval dark brown necrotic sunken spots located mostly on the leaf tip.

10. PATHOGEN The conidiophores were branched, straight and golden brown in colour . The conidia were golden brown in colour , produced in long branched chains, obclavate in shape, with short conical flask. MODE OF SPREAD Primary : Ascospores Secondary : Wind borne conidia

11. SOOTY MOULD Causal organism Cladosporium , Aureobasidium , Antennariella , Limacinula , Scories , and Capnodium .

12. SYMPTOMS Sooty mould is a fungal infection that is secondary to an infestation of aphids or mealybugs . Aphids and mealybugs are pests that suck moisture out of plants, and leaves a clear, sticky substance called honeydew behind on the leaves. The honeydew creates a moist atmosphere, which eventually develops into sooty mould.

13. RUST Causal organism : Phakopsora pachyrhizi Symptoms The fungus creates round black or brown spots on the leaves. The fungus is self-limiting, and does not spread beyond the spots that are affected.

14. IDM These diseases can be prevented by taking a few precautions. Water infrequently and only in the early morning to allow excess water to drain and evaporate. Water the soil and avoid watering from overhead. Spray the any fungicides.

15. REFERENCES http://agropedia.iitk.ac.in ecoursesonline.iasri.res.in/mod/page/ view.php?id =9201