Botrytis blues

According to numerous reports I've received, up and down the country it has been a really bad year for allium diseases, especially during the late ripening process in the ground or in storage. The main culprit is a fungus called botrytis, although there are several types of botrytis that act in slightly different ways. You may know them commonly as grey mould or neck rot. Botrytis leaf blight, or leaf blast (below) is a less common fungus, and certainly not one I've witnessed personally.

The important things to know are that the spores overwinter on infected garden detritus and leaf tissue. It can also store on dirt piles in storage sheds and there are reports it can survive on seeds for 3 years and then transmit to the emerging seedlings. As well as spreading through the soil via the mycellium, spores can also be spread on the wind so as you can see there is a wide scope for being affected at some point or other, even in greenhouses.

The best time (or worst depending on your viewpoint) for infection is during cool, moist, humid conditions which for us in the UK is during mid to late summer when we're thinking of getting our onions up. With the cool summer we've just had you can see why botrytis infections have gone through the roof this year. The botrytis will enter the onion through the tiniest of wounds in the skin or leaves, or via the succulent necks after the tops have been removed.

There are a number of things we can do to minimise losses apparently. First of all consider immersing your seed in a suitable fungicide prior to sowing. For this purpose I have acquired some Rovral fungicide and will be doing this to my seed next season for the first time. If growing in the greenhouse, make sure everything is scrupulously clean and with this in mind I will be giving everything a good spraying and drenching with Jet 5. I'm reliably informed that another, cheaper product called Red Label will also do a good job. Failing that, try a solution of cheap bleach, and add a dash of bleach to your water butts to kill any pathogens lurking in the water.

During the season make sure that you remove all weeds from the greenhouse borders and edges, or from the outside beds. Any onion debris infected or otherwise should be cleared and disposed off, although not on the compost heap. Do not apply nitrogen in the mid to late season of the onion's growth, as this will delay ripening and increases the likelihood of storage losses as the tissue will be too soft and therefore susceptible. Do not water 2 to 3 weeks before lifting and apply a late spraying of fungicide (Rovral) just before lifting when it's not raining or rain is forecast. When actually lifting take extra special care not to damage the onion's tissue, and consider letting the foliage die back naturally rather than cutting as is advocated by most of us in the showing game these days. I've always cut the tops off which I think should be fine if you're ripening off in the house but if you're leaving them in a garage, shed or other outhouse then it may be advantageous to leave the foliage on to dry out and die back naturally. Cool, dry conditions with good airflow are best for storing onions. Ivor Mace has his in a spare bedroom I believe.



It has been a disastrous year for storing shallots for much the same reason. I know of one grower who binned several hundred shallots that all went rotten with botrytis, and I myself have also had to discard about 60% of my crop. After a few 'giveaways' I only have 15 bulbs left for replanting. Dave Thornton reckons he suffers very few losses and the precaution he takes is to scrape the base plate of the bulb so that it is moist. This is then dipped in a Rovral solution to the recommended manufacturer's rate and he is convinced this is why he gets very few rotten bulbs, so I will be doing that to my remaining shallots this weekend hopefully. Another problem with my staged shallots this year was a marked purple tinge to the ripened skins, which I have also suffered from time to time in the past. DT informs me that this is a fungus called 'psytocyanin' and is the result of fluctuating storage temperatures between night and daytime. As I store mine outside on a wire rack I can see that this would certainly have been the case this season, the night-time temperatures this year in June/July resembling much cooler climes. I shall be taking steps to store them in the greenhouse next season to see if I can improve this, as you will certainly be marked down on condition because of it.

Although leeks are also alliums of course, they do not seem to be affected by botrytis as far as I can tell.

Every action has an equal and opposite reaction

One of the downsides of being one of the best looking men in the World is that God sees fit to counteract your facial good fortune by bestowing all manner of pestilence and disease upon thee!

He has populated the Earth with many creatures that appear to serve no useful purpose and chief among these in my opinion is the flying rat otherwise known as the wood pigeon. Many years ago I planted my cabbages out and nipped back inside for a quick cup of tea before netting to keep the buggers at bay. I'd been gone no more than 10 minutes but when I returned my brassicas had been stripped and a couple of pigeons were hurriedly trying to take off so fat were they having consumed all my hard work!

I'd planted out these kohl rabi with a view to trying to get them ready for the show in July when I found this scene of carnage the other night.

I should have known better than to plant them without protection but nethertheless it still pisses you off when you see it. My favoured method of deterrent is some string above the plants with some old CD's dangling down just above the plants. I was told a few years ago that pigeons don't like to see things above them and whenever i've done this I've never had problems with them so it does appear to work despite the plants still being easily accessible if they so wished to take another gobble. Bastards.

The Casablanca potatoes that i'm growing in pots also have these strange brown speckles on the foliage.

I asked Dave Thornton what they might be but he was as much use as a chocolate teapot, sending the picture text as I did whilst he was on a night out with friends. He was so pissed that he text me back saying that he loved me! I never did find out from him what these marks are so I'll just have to hope they're not significant as these spuds will be coming up in a week or two. In the meantime Dave has decided to choose Llangollen to finally come out of the closet!

On Friday it was time to sow my 'Prince' french beans with a view to having them ready for Llangollen which is now only 11 weeks away. There is a right way up to sow beans and I always seem to get 100% germination when I do it this way. If you look at the 'scar' on the bean you should see what look like two small bollocks at the bottom of it. The beans should be sown this way up, with the bollocks towards the bottom. Kinda makes sense when you say it like that really!

My leeks are looking better than any I've had at this time of the year and I've now put them on their first collars, which are 12" tall, and have run a couple of horizontal supports alongside the plants to support the flags. I've also sprayed them with Dynamec to ward off thrips which have rendered my leeks useless for anything other than local showing in recent years. The thrips inhabit the growing point of the leek, hiding right inside the new growth emerging from the 'button'. So therefore you have to use a high pressure spray to really force the insecticide inside the leaf layers. Spraying over the outer foliage will have no effect whatsoever.

I sat next to Mark Roberts at a DA talk the other night and he wore the self-satisfied smile of someone who had some exceptional leeks growing away. I've seen photos of his Nuneaton plot on Facebook and they really were something to behold, and Mark was hoping to win the National again for the collection of 6 as he did in 2007. Later that night he text me in a dejected state as he'd got back to find just about all of his leeks had gone to seed. Back in Winter some jealous twat had got into his garden and switched off his power. Presumably his plants got a check that night which meant they were doomed from that point on. I hope that person is proud of himself and suffers a premature end to life.

Oh, and as I speak it's absolutely wazzing down outside. Severn Trent......any chance you might actually catch some of it?

And remember the golden rule of life.....

Pests and diseases of vegetables

Had a talk at our Hort Soc last night on the above subject from Dave Thornton, General Secretary of the NVS. I made a note of some quite interesting points so here they are in no particular order whatsoever!

• If your spuds are suffering from potato leaf roll virus (which is becoming more of a problem apparently) dig up the affected plants and tuber immediately and dispose of.
• Sterilise water butts as they harbour all sorts of nasties, particularly in warm weather. Use a dash of Jeyes Fluid, Armillatox or cheap bleach which is just as good.
• If saving your own seed sterilise it with a powdered fungicide.
• Fungicides containing Pencanazole are a good general fungicide, which works on leek rust also.
• Dip brassica roots in a hydrated lime solution prior to planting to ward off clubroot.
• Perlka is another product for the control of clubroot.
• Leek and onion thrips are totally different to flower thrips. An insecticide from the garden centre advertising that it kills thrips will probably be the wrong sort therefore. Use a product called Dynamec and apply with a high pressure spray jet.
• Blight.....forget Dithane as most blights are immune to it. Bordeaux Mixture is about the best product available to the amateur grower.
• Do not use Growmore for potatoes as it is often bulked out with lime.
• Vitax Q4 is the best feed for spuds.
• Most of the above mentioned products are not on general sale. Seek out agricultural suppliers such as CWG in Melton Mowbray.