GREY ROT- BOTRYTIS CINEREA

BY- DAKSHITA NAITHANI

ABSTRACT

Botrytis cinerea is responsible for significant losses in more than two hundred crop species throughout the world. This fungus is very harmful to grapes. In most cases, it causes bunch rot, also known as grey rot. It also provides favourable circumstances for the growth of other organisms which support spoilage. 

It is most damaging on dicotyledonous hosts’ mature tissues, but it generally obtains access to such tissues much earlier in the plant development and remains latent for a long period of time before destroying tissues when the environment is favourable and the physiology of the host changes.

As a result, significant harm occurs after harvesting seemingly healthy crops and transporting them to distant markets, where the losses become apparent. On the other hand, it causes large losses in several field and greenhouse-grown crops prior to harvest, and in some hosts, even at the seedling stage.

 INTRODUCTION

Botrytis blight, is a disease which infects a variety of herbaceous annual and perennial plants. Blights can be caused by a number of different fungal species. Infections thrive in cold, wet spring and summer weather, with temperatures hovering around 15°C. It’s especially dangerous when the wet, dreary weather lasts for several days. It is capable of infecting a wide range of ornamental plants. Two more harmful blights have specific host preferences: B. paeoniae infects peonies, and B. tulipae infects tulips, producing tulip fire. Over thirty species of the genus have been discovered so far. Most of them have only been found to infect a few hosts, with others exclusively infecting certain hosts.

NOBLE ROT

Blights aren’t necessarily a bad thing. In viticulture, for example, when ripe grapes get diseased, the skin becomes more porous, allowing more water to escape from the crop. Noble rot enhances the sugar level of the wine and results in a more flavourful wine. To manufacture some of the greatest wine, the grapes are literally hand-picked one by one to ensure that only those grapes afflicted with the parasitic mould are chosen. Horticulturists may find it beneficial in various circumstances. Moulds are unquestionably beneficial in nature. It is also responsible for the effective tidying up of all the leaves that fall from the trees in October. As a result, the cycle of life can begin again. While noble rot may be quite beneficial in terms of concentrating sugars in the winemaker’s grapes, it all depends on the grape type.

SYMPTOMS AND SIGNS

 Grey mould’s most prevalent symptoms are grey-brown lesions, as the name implies. Lesions are found on various parts of the plant. Small spherical specks, known as ‘pocks,’ appear initially on flowers. These may develop into bigger ones. Symptoms on various sections of potted plants are sometimes only evident during and after storage in cold. Grey mould is a component of the foot rot complex in lettuce, which causes rotting of the foot and plant mortality.  These lesions can surround the stem, causing the plant to wilt and die. Grey mould wreaks havoc on produce. Carry-over infection from infected parent plants kills cuttings in potted plants. It can attack at any point throughout the growth of a plant. Early Botrytis Detection-While various plants will exhibit somewhat different symptoms, water-soaked patches on the leaves are one of the first indicators present. These might be off-white or white in appearance. These patches will eventually become brown. They’ll ultimately wilt the leaf because they’ll cover the majority of it.

LATER BOTRYTIS PROGRESSION

When leaves begin to brown, it’s easy to confuse the rot with other fungal infections. However, when the humidity level rises, spore patches that are greyish and rough in nature will develop. Botrytis cinerea is at its most hazardous at this point, as it can now easily distribute spores. Even a small wind, a spray of water or even trimming damaged leaves can spread spores to neighbouring plants. These spores are easily dispersed, and they may appear as a dust on severely diseased plant material. Sclerotia, or black resting formations, are formed by some species and can be seen on dead plant tissues in late summer. 

Fruit will decay while hanging long , and your blooms will turn grey. The plant will eventually wilt and perish, succumbing to the mould. Even after harvesting, the plants are susceptible to it. If the crop is stored in a place with suitable conditions, the spores can germinate and turn it into a watery mush, thus destroying it.

CONTROL METHODS

DURING CULTIVATION

It’s critical to remove any infected plant components as soon as possible. The contaminated pieces should be transferred in a plastic bag as soon as possible. If the entire plant needs to be removed, follow these steps: To begin, place a bag over the plant, next pull the entire plant, including the roots, out of the ground.

Remove both of them from the place after that. Wash your hands and change your clothes before returning to the same area the infected plant or portions of the plant should never be allowed to come into proximity with other plants, since even the tiniest contact will release clouds of grey spores into the air. The spores will then settle on healthy plants, infecting them. To keep the humidity surrounding the leaves and flowers at a lower level, good ventilation is required. When rain is predicted, it is best to cover outside crops with a plastic shelter such as a poly-tunnel.

 BIOLOGICAL CONTROL

Several microbes have been shown to be effective in preventing grey rot in a range of crops.  Because of its capacity to inhibit the development of spores, Clonostachys rosea is utilised to combat and prevent its assaults. It is not the only species that fights; various species of nematode have also been employed to effectively reduce grey mould.

 A few trains of Trichoderma harzianum have an antagonistic effect on the development of several  crops, and the genus Bacillus have been identified as being capable of producing compounds that inhibit its progress, which can be used to prevent damping off in infected flowers and fruits.

FUNGICIDES BASED ON NATURAL EXTRACTS

Plant extract treatments are sold particularly to prevent infection and development. Extracts of citrus seed, thyme, mint, garlic, and pepper, to mention a few, have shown satisfactory effects. The components may vary, but many of them work by blocking mycelium growth.

BIOTECHNOLOGICAL IMPROVEMENTS

In the lab, scientists have succeeded in creating transgenic plants that are unaffected by the introduction of a resistance gene. A kind of inhibitory protein is encoded by this resistance gene. Plants are more resistant to fungal assault when they are inhibited.

WHAT TO DO WHEN PREVENTION FAILS

One of the most challenging aspects is that it has a proclivity for adapting to various fungicidal treatments. It has the ability to build resistance to frequently utilised techniques. One will also need to change their treatment techniques from time to time to make it more difficult for the fungus to acquire that immunity. A smart approach to accomplish this is to alternate your treatments between organic and microbiological techniques. Foliar sprays can protect your plants and stop development before it starts. Adding soil microbial treatments adds additional safeguards to the soil, which are beneficial.

 ORGANIC TREATMENTS

If the plant is sprayed with Neem oil on a regular basis, it can help to prevent fungal development. It can also help to keep pests at bay. Liquid copper fungicides have been shown to help reduce spore infection in plants. To safeguard your plants, use this fungicide every seven to ten days from the start of blooming till harvest.

Potassium bicarbonate works well as well. Green Cure Fungicide is one type that is widely used in organic farming. Usually combined with water, this powdered solution may be sprayed on a daily basis to minimise fungal development. 

BACTERIAL TREATMENTS

Alternately employ a Bacillus subtilis-based solution to stop fungal disease growing resistant to other organic fungicides. This helps in preventing various types of fungal growth.

Foliar spraying – Infuse the soil with beneficial microbes to keep the soil and plants well-defended. It helps avoid infections, but they will also make it easier for the plant’s roots to absorb nutrients.

IS IT DANGEROUS TO HUMANS-

While the majority of people are unaffected, it can induce an allergic response. This is a kind of hypersensitive pneumonitis also known as “winegrower’s lung.” It is seldom fatal, but is quite painful and needs medical attention. They can cause lung inflammation if inhaled in large amounts.

While it can be caused by a number of factors such as different moulds it is best to avoid this by removing any mould before it spreads all over.

CONCLUSION

Botrytis cinerea is a grey fungal mould that costs billions in crop losses each year across the world. It’s also the most frequent microbe responsible for fruit and vegetable post-harvest deterioration, especially towards the conclusion of the blooming phase, and mostly in outdoor crops exposed to rain and humidity. In most cases, it’s a horrible situation. It wreaks havoc on many kinds of fruit crops, including strawberries, raspberries, tomatoes and various others. It can, however, be extremely beneficial to a limited number of people. Late season grapes have shown that this mould causes their grapes’ sugars to concentrate. This gives the finished wine a considerably more strong flavour, as well as honeysuckle-like flavour notes. The availability of the sequence has sparked the generation of high functional analysis to unravel the processes behind this species’ wide range.