Types of coconut leaf diseases and its prevention

Types of coconut leaf diseases and its prevention

Coconut trees are always prone to some diseases. A few of them can also be very harmful, and some can very slowly start affecting the coconut tree by gradually beginning to reduce the overall yield. Here is a brief on the diseases that can infest the coconut palm plant and affect coconut planting at large. Some of the most common coconut farm issues include several fungal and bacteria-related diseases. 

Leaf rot:
When a coconut tree contracts any form of leaf rot, the leaves usually tend to change their colour and turn black. The younger leaves can also break off very easily. The tree will then turn weak resulting in a very low yield. It is recommended to use a multi-micronutrient fertilizer, which is a multiplex coconut mix of 1 kg, it helps with producing regular flowering, better quality, and so much improved yield with larger-sized nuts. This fertilizer is also a good mixture of Iron, Manganese, and several other micronutrients. 

Leaf blight:
This type of disease is majorly caused by fungi, Peastalozzia palmarum, and the Bipolaris incurvata. Initially, there will be a visible appearance of the yellow-brown spots that appear on top of the leaflets from the lower fronds. This then gradually enlarges and tends to turn grey on the coconut planting. In several of the advanced stages, there are always so many specific spots that tend to form really large brown shards giving a scorched appearance. Applying kitchen ash can help with drainage in waterlogged lands. In the case of an occurrence of very severe infestation, it is advisable to spray the coconut leaf with 1% copper fungicide.
Some of the most common symptoms that can occur in the leaf blight in a coconut leaf from the coconut planting. These are found when the leaf starts having visibly large spots and prominent yellow-brown spots start to show on the entire leaflet. This will also then develop into several surrounding grey centers and some dark green borders; The lesions coalesce and can even form large necrotic patches. These are the tips that are usually part of the leaflets and can eventually end up turning from healthy to grey. It is notable that the canopy also has a blighted appearance. Fungus is the most prominent cause of the occurrence of leaf blight and it cannot be mistaken when seen visibility on the coconut planting. It is obvious that fungi, in general, will colonize young, somewhat wounded, or possibly weakened tissues; therefore this form of disease emergence is highly favoured by regular high rainfall as well as high humidity.
The disease usually tends to merit its control in the coconut nurseries as the possible infections of the mature coconut palms are rare; It is also appropriate for the broad-spectrum protective fungicides to be adequately applied.

Coconut cadang-cadang viroid:
The leaves usually tend to grow in a much smaller size and can always fail to unfurl. Overall this begins to give a very choked appearance that can usually end in the overall death of the coconut palm plant. To fully avoid this possibility there is the option to spray organic manure or fertilizer which can be used to prevent such diseases and increase the yield of the palm. 
Some of the very prominent symptoms are visible when the nuts look more rounded when compared to the previous years. These nuts can exhibit scarring on the surface; a few spots on the leaves; and some stunted inflorescences with the tip of the necrosis; the leaves also begin to drop in size and quantity, ultimately in the death of the palm. The major cause is the presence of the viroid present in the coconut planting. 

Grey leaf spot:
In the case of this disease, you will find minute yellow spots that can be surrounded by several greyish bands that come on the surface of the grown leaves. Slowly these spots can even turn fully greyish white leading to the complete drying of leaves when the infection turns severe. Some varieties that have the disease may show no symptoms on the coconut planting, while others exhibit partial yellowing of leaves which begins to spread to the leaf tip; the necrosis of the petioles can even cause the leaves to eventually die and hang from the palm canopy. The leaf hoppers majorly transmit this disease. 

Bud rot:
When a coconut tree is infected by the bud rots, it can tend even to become fatal as this disease is majorly caused by the fungus 

Phytophthora palmivora 
All the young palms that are under 5-20 years old, which are grown under dense plantations are particularly vulnerable to the disease. These incidences are common during the wet season with high relative humidity. At the initial stage, slight withering and drooping of the spindle leaf can eventually occur. A slimy mass is formed around the root of the terminal bud and the surrounding tissues as it tends to degenerate into a foul smell that starts to attract flies. The coconut palm plant’s crown can also be severely infected and can even finally drop off. It is advisable to also start following adequate safety measures to prevent this. The affected palms usually come with a slanting terminal bud that can mostly be cut off and burnt. By applying a borax mixture, we will be able to remove the infected dead tissues. Some of the common symptoms are when the leaves start rapidly turning necrotic; necrotic spots also begin to show on the bases of the leaf; The unopened spear leaves can also be pulled away from the plant very easily; This results in the removal of unopened spear leaves thus revealing a soft, pink-red tissue which can emit a very foul smell; The leaf necrosis can easily spread through the central crown leaves and the woody parts of the plant that may be water-soaked. These pink lesions frequently have many dark borders around them. Interestingly, coconut palm plants are most susceptible to Thai disease when they are between the ages of 14 and 40. Although this illness affects all areas where coconut plantings are grown, it is more common in rainy regions. However, it is manageable with proper hygiene habits and the application of effective and systemic fungicides. A coconut plantation's total demise is frequently caused by the diseased waste and dead trees that surround it. Irrigating the trees in the morning to allow for surface drying over the day is one simple technique to stop this.

Disease management in coconut farming

It is key to always adopt good agricultural and agronomic practices will serve to be handy for overall pest avoidance. That is why they say prevention is always better than cure. Planting coconut seeds with correct spacing and one that is fully exposed to sunlight are some of the best agronomic practices to avoid infestation by harmful pests such as the rhinoceros beetle, the disastrous red palm weevil, and the pestering rodents. Several shallow planting can often lead to lots of heavy incidences of the red palm weevil creating pits and when the coconut seeds are planted in these shallow pits they begin to get exposed to bole regions and several proliferating roots that tend to invite bole entry of the red palm weevil. That is why it is recommended to never mulch the coconut seeds with coconut leaves, especially during the early stage of establishment. The poorly-drained soil can easily get very unsuitable for coconut planting and the coconut seeds in these water-logged conditions could invite skipper butterfly attacks as well as many root grub incidences. With timely and effective crown cleaning, the farmers can greatly reduce the damage that tends to be caused by the coreid bugs and the coconut eriophyid mites. Some effective ways to curb the infestation of pests are by actively avoiding injuries to the palm and by effectively cutting the entire petiole from 1.2 m onwards, it is advised that the trunk is warded off from all possible red palm weevil attacks. Also, look to avoid succulence by the excess application of vital nutrients. Farm hygiene and adequate removal of rhinoceros beetle from the breeding grounds is probably the foremost step in managing a coconut plantation from the rhinoceros beetle. With the right soil-test-based nutrient application that goes along with dolomite, the possibility of biomass being recycled through raising the quantity of the cowpea in the palm basins along with the incorporation that happens during the flowering stage and one which is a sure technique to improve the coconut palm plant’s overall health after a string of invasions by the coconut eriophyid mite and leaf-eating caterpillars.                                                               

Since the many wounds on and around the trunks of the coconut tree can oftentimes predispose the palms to several infections, it is through stem bleeding pathogens that adequate care be taken not to injure the stem base while undertaking any ploughing activity. This will help to avoid trash burning near the very base of the palm. Also, isolation of the diseased palm can be a surety to keep it far from the healthy coconut plantings by ideally digging a trench around the affected palm and safely avoiding flood irrigation. This step will help to check the spread of all the basal stem rot diseases. Application of farm yard manure, a nice neem cake, as well as the recommended dose of nutrients and moisture conservation, can greatly help protect the coconut husks.  

Use of Mechanical Tools in Coconut Planting                                      
The use of mechanical devices as well as the direct involvement of mankind can be classified as a mechanical way to enhance a coconut farm’s compatibility with all techniques. Thus the collection of the emerging adult beetle that comes with white grubs during June to July, makes use of all the light around it, and traps it and by effectively monitoring the pest, we can reduce the havoc that a white grub can create. Also, the mechanical hooking of the rhinoceros beetle is largely perhaps the most convenient method of management that almost any marginal farmer can adopt. Banding the entire palm trunk using a nice polythene sheet or with metal bands can help prevent rodents from climbing up to the crown. Also by tying the fertilizer gunny bags on the crown section of the coconut tree, baiting with traps can be practiced for effective rodent management. The establishment of light traps could also help both in monitoring and reducing the population of the entire slug caterpillar from several moths in the endemic tracts of the coconut farming regions.     

Biological Suppression in Coconut Farms                                                    
Biological pest suppression is for sure the most ecologically sound and definite environmental-friendly approach that can slowly create an impact with several long-term effects. Some of the many classical examples in the areas of coconut pest management come under this category of biological suppression. Applying an entomopathogenic green muscardine fungus, or the paste of Metarhizium anisopliae on the entire breeding pit can act as an effective low-cost and farmer-friendly technology in creating sustainable management of the rhinoceros beetle. 

With the right and judicious integration of all the right techniques to curb pest damage and disease management, it is needed to accommodate a coconut planting and maintenance technique that is need-based, with sustained scouting and proper surveillance. These are some of the key factors that help to accomplish adequate plant health management for the enhanced productivity of the coconut. Having a good social outreach program through these tools would be very realistic in the long run and more sustainable in terms of coconut production. Therefore by successfully implementing the integration of the IPDM practices, that correlate with other crop management components, it is possible to ensure a cost-effective production of the crop and its essentials in making the farmer much more competitive. This is largely why coconut farmers can boldly face the challenges of an ever-changing agricultural scenario.