and this from the electronscope. Here are some general tips for managing Botrytis. i am sure you know, but others finding this thread might not, so perhaps as good a place as any to share the data from Iñaki García
Control methods
During cultivation
It is very important to get rid of any parts of the plant that are infected with Botrytis. The infected parts should be removed and immediately put in a plastic bag. If you need to remove the whole plant, you should follow these steps: first, put a bag over the plant without touching it. Then take the plant out of the ground, including the roots. After that, remove the bag and the plant from the growing area. Before you go back to the growing area, wash your hands and change your clothes. You must never allow the infected plant or parts of the plant to come into contact with other plants, because even the slightest contact will send clouds of gray spores into the air. These spores will then land on healthy plants which may then get infected.
As for the crop, it is important that the plants have enough space and that the leaves do not touch each other. Good ventilation is essential in order to maintain slightly lower humidity around the leaves and flowers. For outdoor crops, it is advisable to cover the plants with a plastic shelter like a poly-tunnel when rain is expected. This prevents the plant from getting wet.
It is also important to be vigilant against pests such as caterpillars which can cause damage to the cuticle, which allows B. cinerea can exploit to enter the plant more easily. It's easier for the fungus to infect plants that have been damaged by chewing pests. Other insects like thrips can carry and spread Botrytis spores.
Biological control
Several micro-organisms have proven to be successful in controlling B. cinerea in a wide variety of crops. Clonostachys rosea (= Gliocladium roseum) is a fungus that is used to combat and prevent Botrytis attacks because of its ability to suppress the production of spores. C. rosea is not the only organism that fights B. cinerea. Some nematode species have also been used to control gray mold effectively.
Some strains of Trichoderma harzianum have been shown to have an antagonistic effect of the development of B. cinerea in some crops. And some bacteria of the genus Bacillus have been identified which are capable of producing substances that inhibit the growth of B. cinerea, which are useful when applied to infected flowers and fruits and the soil to prevent damping off. However, the effectiveness of these organisms depends on various factors such as environmental conditions and the developmental stage of the crop. For crops like strawberries and blueberries, bees have also been used successfully to improve the dispersion and efficacy of these antagonistic bacteria. If a certain amount of beneficial micro-organisms are placed in the beehive, they will be distributed around the crop by the bees.
Fungicides based on natural extracts
Many plant extract preparations are marketed primarily to prevent the attack and development of B. cinerea. Good results have been achieved with extracts of thyme, citrus seed, oregano, mint, garlic and pepper, to name but a few. The components of these extracts are diverse, but many act by inhibiting the germination of conidia or preventing the development of the mycelium.
Biotechnological improvements
Scientists have succeeded in developing transgenic plants in the lab which are not affected by B. cinerea by introducing a resistance gene. This resistance gene encodes a type of protein called polygalacturonase inhibitory proteins. As mentioned above, Botrytis produces enzymes that allow the fungus to infect host cells and some of these enzymes are endopolygalaturonases. Inhibiting this protein means that plants are more resistant to fungal attack.
Noble rot
Botrytis Cinerea is a very common mold, which spreads very easily, both in the vegetable drawer of your fridge and in live crops in the field. Although it is possible to combat this type of mold, it is difficult to get it under control. That’s why it has been such a difficult problem worldwide!
However, Botrytis is not always harmful. For example, when ripe grapes are infected in viticulture (grape-growing), the skin becomes more porous and more water can evaporate from the fruit. That benefits the sugar content and produces wine with a better bouquet. This is also known as ‘noble rot’. To produce some of the best ‘Botrytis wines’, the grapes are literally handpicked one by one, so that only those grapes that have been infected by the parasitic mold are selected. In some cases, then, Botrytis can be a blessing for horticulturists. And in nature, molds are certainly a blessing. We have Botrytis to thank for the fact that all the leaves which fall from the trees in the autumn get tidied up so efficiently. And that means that the circle of life can begin anew.