Topic: How bad is late blight and carrot fly on your site?

[g-uk]

Late blight has hit our site every year, for the last 4 years or so, without fail. It is always bad enough that any remaining potatoes are infected and nearly all tomato plants are killed before fruit can ripen, even when grown inside a polytunnel. A few lucky tenants manage to keep their greenhouses sealed enough to avoid it.

Carrot fly is now so bad that it is impossible to grow carrots without a barrier, and even then carrots still get the fly to some extent.

Onion Fly is also so bad that to get good onion requires total isolation barriers.

Basically it is not worth growing tomatoes, onions or carrots on site without extreme isolation methods.

Interestingly a school around 6 miles away seems not to have any problem with carrot or onion fly.

Is bad allotment keeping practice to be blamed?

[Jayb]

I'm not on an allotment site and don't have any close veggie growing neighbours. But I do have yearly problems with Late Blight more so with potatoes but it usually gets tomatoes a bit later. Carrot root fly makes a mess of both carrots and parsnips here if grown without protection. I think bad practices might make issues worse but from my experience if you are in prone areas then not much you can do other than take what precautions you can. I find that debris netting keeps carrot root fly at bay with the bonus of making a micro climate which the crops love.  I do despair sometimes with blight but I still enjoy growing tomatoes and potatoes, though getting a harvest is never certain.

Welcome to Allotments4all g-uk.

[g-uk]

Sorry to hear you still get hit pretty bad in your garden.

I'm guessing it's a problem everywhere. I think it's worse on allotments though. Four years trying to grow tomatoes inside a polytunnel for added protection and no fruit gets to ripen. The same is true for all of the outdoor tomatoes on site.

I grew carrots well one year in pure compost surrounded by 1 metre tall environmesh. However even with double layered environmesh small holes get made. The result was that the second year there was about 50% infection.

Buying new mesh and compost each year would make them so expensive.

I have given up on tomatoes, carrots, and onions, and plan to grow more beetroot, sweetcorn and beans.

I think it would take GM to be able to grow a tomato on my plot.

[winecap]

Carrot fly is bad enough in our area that I totally failed with carrots for the first ten years trying to grow them. I've now got pretty good at avoiding the fly and have carrots for most of the year. I am still pulling carrots at the allotment now and the first of the new season should be sown this week. My early carrots go in the greenhouse border. Hopefully I will be pulling them before the carrot fly realize they are too late. They will be eaten ready to plant tomatoes in their place.
Later carrot sowings go into a builders bag - the sort of thing that bulk sand is delivered in. So long as you don't position it too near to fences or hedges, the carrot fly wont find them, or at least very few will, and you can adjust the soil in the bag to suit the carrots. My third carrot sowing is also into a builders bag, and is late enough that most of the carrot fly have been and gone.
In short, the carrot fly is terrible, but the carrots are great. There is something extra satisfying about succeeding with something after years of failure. Don't be put off because method 1 doesn't work. There are lots of other options.
As for late blight -it comes most years. The early potatoes aren't affected and I only grow red alert and Latah tomatoes outside. These reliably ripen before blight. As for maincrop potatoes, I just dig them up when the blight hits and don't find it a problem. Presumably the yield is reduced, but I still have sacks of potatoes. The indoor tomatoes don't seem to suffer but I don't grow any of them in pots - they are all in the greenhouse border and I make a point of watering into sunken pots so the soil surface stays dry. I think it helps keep them safe.

[g-uk]

Glad that your managing to have some success.
I'm going to stick with crops that are less plagued.

[BarriedaleNick]

Carrot fly is endemic on our site but me and my mate Mike still get a decent crop.  He is an ex farmer and gets a fantastic crop every year so basically I have copied what he does to a certain extent.   We both use barriers - I use mesh and have had the same bit of mesh, which I got for free, for the last few years.  He uses net curtains (from the market for a quid)  and plastic sheeting and gets virtually no fly.  Some may say it isn't worth the effort as carrots are so cheap but I am still picking carrots and there is nothing like a fresh carrot.

Blight is also pretty much a certainty at some point in the season but just last year I had the biggest toms and spuds crops I have ever had - I still have bags of spuds in the garage and a freezer full of passata.  However many folks on our site don't bother with out door toms any more - mostly down to blight I guess.  My toms in my little garden poly don't get affected.  I get blight alerts from blightwatch and spray with a very minimal amount of copper sulphate when there is a local alert or when I see the dreaded brown patch.   Last year I tried Sarpo Mira - blight resistant variety which gave me a huge crop and no blight even though they stood the full season - good spuds too.  I also try to plant defensively - leaving plenty of space around toms and making sure they are really hardened off before going out.  Doesn't always work - season before last I had to cut most of my toms in half due to blight but I still got a decent enough crop.

We get white onion rot and leek moth as well - This year I am trying the garlic/onion mush prevention thing and Ill have to do something about the leek moth although Mike 2 plots down doesn't seem to get it.

[Digeroo]

Blight is proving rather a frustration.  But I have had good potatoes every year even in the rain. Tomatoes are proving more of a problem.

Some of my carrots have had problems but most are ok.  No problems with parsnips.   I am on a very windy site and the flies do not seem to like it much.  I think I may start to throw over some netting also because they seem to like it underneath.

[g-uk]

I'm glad everyone is still managing to find ways to keep growing despite some of the pests.

I tried a net barrier (environmesh) for my carrots. I had great carrots the first year, but the year after the fly managed to get in. Maybe I just got unlucky. The temptation of fresh carrots will probably result in me trying again at some point.

[Robert_Brenchley]

Blight is endemic on the allotments, and after a couple of bad summers it becomes so bad that the disease is everywhere after a couple of Smith periods. A dry summer gets rid of most of it again, but it's always there. Away from the site, the number of spores in the air would be greatly diluted, with much less chance of infection. I imagine the same applies to the other diseases mentioned.

[Digeroo]

I am still convinced that blight arrives on the seed potatoes.  We had it the first year on a brand new site which had never ever had potatoes grown on it.  It started in the middle, those on the  side with the prevailing wind lasted the longest so it did not come in with the wind.  Those down wind went very quickly.

I have also been trying to convince people not to water over the leaves and stems.  There is no point in creating your own smith period.

[sparrow]

I have also been trying to convince people not to water over the leaves and stems.  There is no point in creating your own smith period.

same for our site - every time I see the hoses come out to give the potatoes a soaking from above...

I grow carrots on my north-facing balcony. I defy a fly to get up 7.5m.

Carrot fly is not too bad on our site, onion fly pretty much non-existent, blight regularly bad though didn't happen last year. If you're on an allotment site you have to expect some bad practices, not everyone's going to be perfect. Or that bothered.

I'm glad everyone is still managing to find ways to keep growing despite some of the pests.

Maybe your site is particularly affected? I had no blight at all last year and had cracking tomatoes, grown in an open culticave to give them a bit of shelter.

[g-uk]

It certainly seems that it is worse in some sites than others.

[laurieuk]

We cannot grow carrots because of badgers so I grow them in large pots raised on an old table then the fly cannot get to them. Tomatoes I get very good crops growing the blight resistant varieties and potatoes are ok if you cut the foliage off as soon as it comes, the potatoes   are formed by this time and then  the rain does not take the blight to the crop. Carrot fly over winters in the soil so if you use a brier you can trap them inside.

[Plot22]

Blight none at all last year but most years it starts at one end and works its way down.
Carrot fly I got it the first couple of years then made a 3' barrier worked until the wind took the flies over the top. I now have a 5' high enviromental mesh tunnel in which I can crawl & turn around in. I close it at the back of me and I have no problem with carot fly. In fact I grow 4 rows the width of the allotment and the family and ourselves use them all. I know some people keep them in the ground but my experience is that the go hairy and get eaten by slugs so by late September all mine are up and in the family's freezers.

[mrrigsby]

Potato blight and carrot fly seem to be inherent problems on allotment sites where bad practise by a few causes manifold problems for many. Notwithstanding these problems at our site, it is possible, with a little extra effort, to successfully grow carrots and potatoes. Being in SW I can get an early start with potatoes, so grow 1st early which are then used before blight becomes a problem. I plant Sarpo Mira as a maincrop, they are not affected at all with blight. I grow all carrots under a suitable physical barrier to combat carrot fly, even 'show' carrots grown in barrels, and this works well. As I said, it's extra work, but it is still possible to succeed.

[Robert_Brenchley]

Blight varies from year to year. There was little or none on the site last year. For several years before that, however, it was really bad. It was obviously endemic on the site, and it only needed a couple of Smith periods to let it loose again.