Thursday, 2 June 2011

Using barriers to keep pests off vegetables.

I  had covered the brassicas with netting to keep the pigeons off them.  The netting was not fine enough to efficiently prevent cabbage white butterflies Pieris brassicae  getting to the plants but I know that some people are using scaffold netting to do this job.  They use water pipe to form hoops to put the netting over and keep the net off the plants.  Both cabbage butterflies and cabbage root fly Delia radicum would be excluded from the plants.

Although this is a very effective method of pest control, I cannot be bothered with doing it.    I would rather be able to get to the plants to see how they are getting on.  I also like to hoe up the brassicae plants.  I do this for two reasons.  The first is to help to prevent cabbage root fly from laying eggs near the stems. The second reason is to encourage root production from the stems.  This will help in stabilising the plant when it gets bigger.  

Today, I took off the final net covering the brassicas.  When the cabbage white butterfly begins to lay eggs and the caterpillars start to hatch out, hopefully I will be able to remove them by gloved hand.  I have done this successfully for a couple of years now.  

I planted some radish and some rocket in the brassicae bed between the other plants.  They will be cropped long before the big brassicas overshadow them.  

I took down the netting from  around the runner beans.  This netting was not being used as a pest barrier but rather a wind break.  The runner bean plants seem to appreciate being out of a cold wind early in the season.  Most of my runner beans are Aintree.  It is a particularly early one and it has already gone up the supporting canes about 600mm.  I gave them a weeding and watering today.  

Now we had to make a decision about the onions.  I have been using plastic cloches to keep the onion miner fly Phytomyza gymnostoma off the onions and I had been advised that it was fine to remove the barriers now.  It took a lot of effort to convince myself but I did take the cloches off and put them away.  I watered the onions with a good dose of diluted comfrey liquid and they seem to be doing all right.  

I will be putting the cloches and enviromesh back onto the leeks around the end of July as a barrier because Phytomyza gymnostoma has a second generation in late summer.  While the larva are eating other people's onions and pupating, I will have a respite and the onions will be able to develop without protection - or that is the theory anyway.  

I hate having to protect the onions and leeks.  These are the two vegetables that rarely had any problems at all in the olden days and could be left to fare for themselves during the summer.  

I do not take off the enviromesh covering the carrots.  After thinning them out on Tuesday, it was too much of a risk to leave them exposed.  It seems that the carrot root fly Psila rosae does not have a dormant period as far as I have experienced.  So I leave the barrier on all season.  Weeding and thinning is a faff but worth while when you see the lovely carrots that you have produced under the netting.  

I sowed more Hamburg parsley and spinach.  I made a drill with the back of the rake then watered it with dilute comfrey liquid.  A little mychorrhizal fungi spores were put at the bottom of the drill and the seeds were sown on top.  The soil was carefully replaced using the rake and tamped down gently.  I like to water the seeds immediately after sowing and then regularly until they germinate.  

I am getting about a kilo of strawberries off the plants every time I pick them.  Maybe five 25 foot rows is a little excessive but I do like strawberries.  

I keep taking the immature Webb's Wonderful lettuce for salad leaves.  As I have taken out the rocket I cannot add these to the leaves but I am using the spinach instead.  

I have been given 6 beefsteak tomatoes by Fred.  I have bought four of them home to put into the greenhouse but two are in pots on the allotment.  I used Fred's home made compost to plant them in putting in mychorrhizal fungi next to the roots.  These outdoor plants will probably get blight before they fruit heavily but the ones in the greenhouse will compensate - hopefully.

I took another crop of sweet cicely and put it into the comfrey bins.  Hopefully this will add to the potency of the comfrey liquid.  It certainly seems to be doing everything good.  Have a look at the photographs for the end of May.  

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