IPM Packages for Crops

disease & viruses

Fusarium Wilt [ Fusarium oxysporum (Hypocreales: Nec- triaceae)] Fusarium oxysporum f. sp. ciceris (FOC) is one of the widely distributed diseases of chickpea in almost all conti- nents includ- ing the Americas, Africa, Europe, and Asia, and cause yield loss of up to 10–100%, depending on varietal susceptibility and climatic conditions. The pathogen was re- ported to have eight races from all over the world. It affects all growth stages. Wilting of top leaves, shrinking and curling of leaves, plant stunting, reduced root growth, and damaged tap root system are typical symptoms. Early wilt causes more damage than late wilt. In Asia, it is also reported at the seedling stage. Warm, moist soils are favorable for this disease. Synergistic interaction between fusarium wilt and root-knot nematodes (e.g., Meloidogyne artiellia, M. incognita, M. javanica ) has been observed in chickpea roots, hence the presence of nematodes in the field signifi- cantly increases wilt incidence. Damage done by nematodes facilitates the disease’s infection on roots and these nematodes also break down resistance to fusarium wilt. Controlling nematodes will help to reduce the incidence of fusarium wilt. This disease can be spread by water splash, movement of infected soil, plants, and seeds. Crop rotation, field and crop sanitation, and the use of resistant and early maturing cultivars help manage this disease. Seed treatment with Trichoderma spp. and Pseudomonas fluorescens can be used to reduce nematode incidence and Trichoderma spp., Streptomyces pseudo- monas, Penicillium oxalicum , Pythium oligandrum , and Bacillus spp. can manage fusarium wilt of chickpea.

Dry root rot [ Macrophomina phaseolina (Botryosphae- riales: Botryosphaeriaceae)] It is a soil-inhabiting organism capable of infecting chickpea at any crop stage, but most commonly infects chickpea at post-reproductive stage in dry and warm regions. Yield loss information is not available. Symptoms of this disease include drooping of petioles and leaflets on the tips, dark, rotten tap roots, presence of gray fibrous fungal threads on the taproot, and dry root. High temperature and low moisture are favorable for this disease. Deep plowing, removal of debris, early planting, adequate plant spacing to avoid overcrowding, and competition for water, can help in managing this disease. Resis- tant cultivars are available. Seed treatment with Trichoderma spp., Streptomyces sp., Pseudomonas sp., Penicillium oxalicum, Pythium oligandrum , and Bacillus spp. can manage fusarium wilt of chickpea. Phytophthora root rot [ Phytophthora medicaginis (Peronospora- les: Peronosporaceae)] Symptoms of this disease can develop from seedling emergence to near maturity. It causes wilting, chlorosis, and rapid death of the plant. Taproots of the infested plant are girdled by brown and black zones of the rotting process. Warm and wet soil conditions are favorable for this disease. Resistant varieties are available to manage this disease. Late planting to avoid wet and soils could be useful. Biological seed treat- ments with Trichoderma harzianum, Pen- icillium oxalicum, Pythium oligandrum, Pseudomonas fluorescens , and Bacillus spp. help manage this disease.

VIRUSES

Alfalfa mosaic virus Chickpea plants become chlorotic and stunted and often have chlorotic and ne- crotic shoot tips. Plants die prematurely. It is transmitted by at least 14 different aphid species, the common one being Acyrthosi- phon pisum (Hemiptera: Aphididae). Bean yellow mosaic virus It causes malformation, mottling, and stunting in plants. Infected leaves get twisted and curled. Flowering and pod formation is reduced and small seeds are produced by the infected plants. This is transmitted by several aphid species in a nonpersistent manner. Cucumber mosaic virus It causes chlorosis, leaf malformation, and stunting in plants. Leaflets show a mild mosaic and reddening of leaf margins. This virus is transmitted by several aphid species. Pea seed-borne mosaic virus It causes filiform leaves, indistinct mosaic patterns, mottling, chlorosis, reddening, necrotic lesions, a proliferation of stems, and abortion of pods. It is transmitted by several aphid species. Chickpea chlorotic dwarf virus It is the predominant cause of yellowing and stunting diseases of cool-season food legume crops in Ethiopia. The disease is also called chickpea stunt disease. It is vec- tored by leaf hoppers ( Aphis craccivora, Myzus persicae ) (Hemiptera: Aphididae) and leaf hoppers ( Empoasca devastans, Orosius albicinctus ) (Hemiptera: Cicadel- lidae).