Thursday, 4 June 2015

Allotment update - pests and diseases

Onion white rot destroys the roots
then attacks and rots the bulb
I have been fairly busy with my allotment and it has (in general) been taking shape nicely.
The big remaining problems are rabbits and also onion white rot, which has devastated my winter onions.
The rabbits put paid to my efforts at growing saffron crocus. I never dreamed that they would eat crocus leaves, but they treated them like fine asparagus and nibbled them off as soon as they showed above ground. In April, I gave up and took the surviving bulbs home to plant in the garden. I may be able to harvest some saffron from them there, but I think they will take a while to recover.
Rabbits were also nibbling my spring-sown onion sets and my Jerusalem artichokes, so I have fenced off the whole of one half of the allotment. I will put wire netting around the whole perimeter later in the year, it's a big job but it will save a lot of hassle in the long run. I've seen a big fox down at the allotments, but he's not making much of a dent in the rabbit population.
My winter onions have been devastated by white rot
The onion white rot is more troublesome. It is a fungal disease and eats away at the onion roots and then rots the developing bulb. Once in the soil, it will attack any member of the onion family - leeks, shallots, garlic or chives. It remains active in the soil (even if no onions are grown) for up to 15 years and is easily transmitted from one part of the allotment to others.
I don't know if the fungal spores were in the soil when I took on the allotment or whether it has been infected by fungus on the sets I planted or fertiliser I dug in. I grew leeks in a different part of the allotment last year with no problems at all.
The winter onions looked pretty good and a small patch on the end of the row still has plants doing very well. However, they may be infected and the rest of the crop has been dug up and put in the black bin at home. My spring-sown sets are not affected and appear to be growing well, although again, they may be affected just not shown any symptoms yet.
Onions were one of my main crops, so this is a blow. There's no chemical cure, so all I can do is transfer onions to the other side of the allotment, fence off the part I know is infected and hope I can contain the fungus. Of course, not realising there was any problem, I have happily walked across the infected land and onto other parts of the allotment. White rot sets tiny spores, about the size of a poppy seed, so they would easily be carried on muddy boots, garden tools or dog paws.
I have some rust on my garlic leaves and a few blackfly on my broad beans, but I pinched out the tops of those this week so, hopefully, that won't become too serious a problem.
The is where we are with other parts of the allotment:
  • My saffron crocus patch has been converted to salad veg (radish, lettuce and spring onion) and is rabbit fenced and pigeon netted. Radish were our first crop of the year and lettuce also doing well.
  • The asparagus bed was not cropped this year. There were just a few spears from the three crowns and so I've left them to build up for 2016.
  • Shallots look healthy; they overwintered well and the bulbs should begin to develop and swell in the next few weeks provided the white rot hasn't got across to them.
  • Garlic was looking OK, but the leaves are now streaked with rust. I don't know how this will affect the growth of the bulbs, the plants are quite large. I might grow these in pots next year, so I can keep them in the greenhouse over the harsher winter months.
  • Corn is doing well, both from pot sown/transplanted and from direct sowings.
  • Broad beans were sown direct in spring and are currently in full flower (they smell beautiful). I've pinched out the tops to encourage the pods to fill and to deter blackfly. I'll definitely grow these again and will try some autumn sowings as well.
  • My peas germinated somewhat erratically (it was so dry in April and May), so I've resown sections and have them netted with micromesh to stop pea moths laying eggs in the flowers.
  • I have several rows of carrots, parsnip and beetroot. They are under mesh cloches and I haven't really checked on them. I know some are coming through, but the dry weather may have inhibited some germination. When I'm back from holiday, I'll need to thin, weed and resow (possibly all three).
  • Runner beans are being grown up three linked cane wigwams. I got some plastic cane holders which clip together to make a ring and you can then push the tops of the canes through holes. It seems to have made quite a strong structure. Runners beans didn't freeze well last year and they're much nicer fresh, so I've grown enough to feed us and give away, but not too many that we'll have a glut.
  • This year I'm trying borlotti beans, which I will allow to dry in the pod and use in stews during the winter. Like the runner beans, they have just been planted out.
  • I planted out purple sprouting broccoli this week and hope to get some brussels sprouts in  by the end of the week. These are netted against pigeons and cabbage white butterflies.
  • Jerusalem artichokes are a new crop for me. Once protected from the rabbits, they are making good growth and should provide an attractive screen as well as a root crop. I'm not sure what we'll do with them. I've had them roasted and they were quite good.
  • My globe artichokes were moved from the other half of the allotment in spring, divided and replanted. They had made massive roots, so it was hard work - almost like digging up a hedge. Happily, they have survived the move and the surgery and seem to be doing quite well in their new location.
  • I am growing some corn for Tom and Lucy. It has done quite well both from pot grown/transplanted and some sown directly. There are two patches and, if we get a good summer, I think it might do OK.
  • Rhubarb was moved from home to the allotment and despite going to a lot of trouble preparing the ground, it doesn't look too happy. It might have been too dry or it might like more light. Maybe it just needs time to re-establish itself?
  • My cider apple trees are growing well and I should get a small crop from them this year. The mature apple tree was pruned and has a decent crop again. The tree that split under the weight of apples has sprouted into growth where I sawed the trunk clean. I'm hoping it might recover as they were nice apples.
  • Gooseberries, blackcurrants and redcurrant bushes will provide a small crop this year, but it's next year when I hope to cash in. I plan to add more blackcurrants (from home) and some raspberry canes and will need to build a fruit cage or the birds and muntjac will have the lot.
  • Finally, I have eight courgette plants (four green and four yellow). They have only just gone in and hopefully will do as well as they did last year. if they do, we will be buried under courgettes.
That's everything. It's been hard work, but enjoyable and interesting. I'm glad I'm not a subsistence farmer or I would be very worried about what I would be eating next year.

My allotment is much more varied than other plots which are often used for potatoes and nothing else. People can't understand why I'm not growing potatoes and give me an odd look when I say that we don't eat that many.
Broad beans and other crops behind rabbit fences and micromesh

Globe artichokes are growing strongly after transplanting

Corn is coming along nicely - just need a warm summer