5 Papaya diseases and their management
Transcript
I welcome you into the last topic of this week that is Important Papaya Diseases and their management. There are number of diseases that cause severe loss to papaya cultivation. Some of them are Damping off, Ring spot, Food Rot, Leaf Curl and Papaya Mosaic. These are considered to be the most important and significant diseases that causes severe loss to the papaya growers.
Damping off of papaya is caused by Rhizoctonia solani and the disease is most prevalent in the papaya nurseries. So the roots or the crown region is affected mostly by this pathogen and the seedlings get killed within a short period of time. The pathogen is soil borne and it survived in the nursery beds mostly. There are IPM practices that are recommended for management of this particular disease that includes cultural biological and chemical control. it is advised that the nursery bed should be well-drained so that there is no excess moisture present on the nursery beds. This should not be excessively irrigated so that a proper moisture level is maintained on the nursery beds. This is highly recommended because this excess moisture favours disease development in these nurseries. Biological control method includes the application of Trichoderma viride at the rate of three to four gram per kg of seed. This is an antagonist of Rhizoctonia solani and Trichoderma can have a good suppressive effect on Rhizoctonia solani on nurseries. So Trichoderma should be applied to the nursery beds before sowing after the seeds. The chemical methods include seed treatment with Captan at a rate of 3gm/kg of seed. It is a protective fungicide and it helps the seedlings to get protected in the early stage of their growth. So these are some of the important Cultural, Biological and Chemical methods that help in us in reducing the Damping off of papaya that is caused by Rhizoctonia solani in papaya nurseries.
The next most important papaya disease is Foot Rot of papaya. That is caused by a fungus Pythium aphanidermatum. This is again important because once the foot is rotten that means the entire plant will be affected and after some time the whole plant wither out. So this particular disease needs to be managed otherwise the entire plant is going to be died. The pathogen is soil borne in nature, it remains in soil and therefore IPM practices aimed in managing this pathogen in soil and plant level.
The IPM practices include Cultural, Biological and Chemical methods and integration of this method can have a good control over this pathogen. Cultural methods include application of irrigation by the ring method so that it avoid water coming in direct contact with the stem. Since high moisture the pathogen to come and reach the plant so light irrigation or irrigation by ring method is advisable so that it prevents water logging and thereby movement of the pathogen towards the plant. Biological control measures include application of Trichoderma viride at the rate of 15 gram per plant and it should be mixed in well decomposed FYM in the root zone at the time of planting. So application of Trichoderma viride along with mixing with FYM should be a very very effective control measure to manage this disease to a significant way. Then certain chemicals are also recommended where Copper Oxychloride is one of those which should be for drenching the soil with two to three liter of Copper Oxychloride at a rate of three gm/liter. It should be done regularly at 15 days interval from the time of planting. So this particular application of chemicals like Copper oxychloride can have a better protection in the later stage. During food formation plants should be sprayed with same solution or Mancozeb at the rate of 2.5gm/liter at the same time interval. So Copper Oxychloride along with Mancozeb they can give very good and effective control of Pythium that leads to development of Food Rot of papaya. If the disease appears or attacks the existing crop then the rotted portion of the plant should be scraped out and there should be application of Copper Oxychloride or Bordeaux at the scraped out area. This can protect the new or in newly injured tissues and it provides a chemical barrier for the pathogen to come and attack on this exposed tissues. So these are the control measures that help us managing the Foot Rot of papaya that is caused by Pythium aphanidermatum.
Next important disease of papaya is papaya Ring spot and it is caused by Papaya ring spot virus. The plants are affected by this virus and it can get spread to the entire plantation within a short time. The manifestation of the disease can be seen like very thin and shoe string-like appearance of leaves in the upper crown and when there fruiting is there then we can see string[1]like ppearance on the fruit bodies which are dark green in color. These are very common symptoms and they are easily detectable on the papaya host. Since it is a virus so it survive in infected plants and cultural and chemical methods has been recommended for management of this particular disease. Cultural methods include early detection of infected plants and prompt removal can check the spread of the disease. Once a plant is seen to be infected with papaya ringspot virus the plant should be uprooted immediately and it should be burnt and destroyed. It will help in stopping the progress of the disease from one plant to other plants. Chemicals that are mostly aimed to manage Aphids which is the vector of this particular virus is the most recommended. An application of Carbofuran at the rate of 1 kg active ingredient per hectare in the nursery bed, at the time of seed sowing is important which can be followed by 2 to 3 foliar sprays of Phisphamidon at the rate of .05% at an interval of 10 days, starting from 15 to 20 days after sowing. So this chemical management of Aphid can have a good protection of the plants because once the vectors are not available in the field or papaya plantation area the spread of the disease is automatically reduced. So these are the important diseases of papaya and that can lead to effective control measures of papaya.
Leaf Curl of Papaya is another disease of papaya that is caused by Tobacco leaf curl Virus and you can see that the leaves are curled inward and downward and this is a common symptom of the papaya leaves which is caused due to leaf curl disease. Since it is a virus the pathogen survived in infected plants and IPM practices are recommended that include Cultural and Chemical practices. So like the earlier pathogen removal and destruction of the affected plant is also recommended in this case. Once a single plant is identified to be infected by the papaya leaf curl virus then the plant should be immediately uprooted and it should be burnt or destroyed. It will help in checking or stopping the progress of the disease within the papaya plantation. Then chemicals that are mostly used for checking the white flies population are to be used that will help in reducing the disease severity in the papaya cultivated area. Soil application of Carbofuran at the rate of 1 kg active ingredient per hectare at the time of sowing along with 4 to 5 foliar sprays of Dimethoate at the rate of 0.5% or Metasystox at the rate of 0.02% or Novacron at the rate of 0.05 percent at an interval of 10 days can have effective control over the white flies that is the common vector for transmission of this particular virus. So these chemical methods for men controlling the vector white flies along with the cultural practices this lead to successful management of these papaya disease. So we have seen that these are the some of the most important papaya diseases that affect papaya cultivation globally and we can have successful management of these particular diseases, by adopting appropriate Cultural, Chemical and Biological methods, with this we can save the potential loss to the growers to a great extent.
Thank you.
