Category Archives: pest&disease

Fly, fly away….

Fruit_fly(1)Drosophila – or the fruit fly; so beloved by geneticists, (well one species anyway).  Apparently they have HUGE chromosomes in their saliva glands.  Very cheap to keep and they reproduce like insect bunnies.

Not very beloved chez nous.   At this time of year the fruit and veg from the plot comes thick and fast.   So do the fruit flies.  The OH has invested in a tennis racket like contraption (called the Executioner)  that zaps the flies but he is losing the battle.   The kitchen and utility rooms are studded with jam jars of cider vinegar into which the flies gleefully tumble.

But the really, really annoying thing about the fruit fly, (apart from generally being really really annoying), is that single one in a glass of wine will taint the wine so badly that the only option is to chuck it away.  The wine is utterly undrinkable.   The taint comes from an enzyme released as the alcohol dissolves the fly.

So cork back in the bottle and a saucer placed on top of the wine glass is the order of the day until they fly fly away (or die at the hands of the OH).

Reading this week: The Caliph’s House by Tahir Shah

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Out damned spot ….

Late_blight_on_potato_leafLate blight has hit the potatoes.   I’ve cut off all the haulms and cleared the debris from the rows.   The combination of wet and warm allowed the oomycete, (water mold), spores of Phytophthora infestans to get a hold.   It is a horrible disease; brown, sodden rotting leaves, lesions on the stems and if left, the pathogen causes the tubers to rot.   We don’t spray so the only option for us onceDSC_0399 blight symptoms appear is to cut the foliage off, clear away the debris and earth up.   We will leave the tubers in for a couple of weeks to let the skins harden and then all will be lifted.  None can be stored.  This isn’t a problem this year as we cut back quite significantly on the potatoes.  

I can never understand where the  sporangia come from; it is difficult to ensure that all traces of a potato crop have been removed from the soil.  A tiny tuber can develop into a potato plant the following year.  Could this be a source?  How many miles are the sporangia or spores blown?  Can the pathogen survive as oospores in the soil?  

I had signed up to blightwatch (http://www.blightwatch.co.uk/content/bw-Home.asp) but hadn’t received any notice of full or near miss Smith Periods.  Smith Period conditions are conducive for the  sporangia germination and spore formation. I’ve just looked on the Potato Council ‘Fight Against Blight’ map page and I see that blight outbreaks were recorded in my outer postcode fairly recently, (http://www.potato.org.uk/fight-against-blight).

As with most years we had planted a ‘Sarpo’ variety.  These main crop varieties are meant to be more resistant to the blight.  I cut the haulms off everything anyway.

Of course I’m now on tenterhooks – will the spores get in to the polytunnel and run amok through the tomatoes?  The humidity in the tunnel means that if the spores get in then blight is inevitable.

I’m keeping the doors shut and crossing my fingers.

 

 

Pestilence – the return……

A humongous rabbit has just lolloped out of the hedge line and there is a mole in the veg patch – I’ve been admiring the parabola of mole hills he/she has left in the bed.  Wood pigeons have been cropping the emerging peas.  I really should be stitching up runs of netting for the strawberries…..

Instead…I’ve been butterfly researching.

Last year I was bemoaning the lack of butterflies.   I’m hoping for good things this year.   Whilst turfing out a kit, aka baby rabbit, from the veg patch, (okay, the OH did the actual turfing out  – I supervised),  I came across this on a patch of nettles.

DSC_0075They are the caterpillars of the Peacock butterfly  (Aglais io).  There were loads of them emerging from webs.  Googling a butterfly/nettle combo to assist the I.D. I discovered that nettles are also an important plant for the Small Tortoiseshell (Aglais urticae), Red Admiral (Vanessa atalanta) as well as a food source for the caterpillars of  the Painted Lady (Cynthia cardui) and Comma (Polygonia c-album).  Good thing we’ve got loads of nettles round the homestead then.   I have recently seen Orange tips, (Anthocharis cardamines), Small White, (Pieris rapae) having a flutter round the radish, and Large White, (Pieris brassicae).  So here’s hoping we have clouds of butterflies this summer.

(PS   I didn’t stitch the netting but I did stuff a slab of concrete in the sliver of a gap left by a gate in the veg. plot fencing as an anti kit measure.)

Pestilence!!!

DSC_0053Two of the gooseberry bushes have gone down with mildew, American Gooseberry mildew, (caused by the fungus Podosphaera mors-uvae).  Drat, drat.  Not all the bushes are affected – just the Careless, (ha! – well named), and the Leveller specimens.  I did think that Leveller was meant to be more resistant to the mildew – obviously not!   I suspect the intermittent showers and sun have built up the humidity and these 2 specimens are quite densely leaved.  The fruits of the affected bush can be washed and eaten but I suspect I will strip them off and thin out the bush to improve air circulation.  The Hinnomaki Red, Hinnomaki Yellow, Captivator and Invicta specimens look fine, (they are all meant to have some degree of resistance to the mildew), so hopefully we will still be able to harvest gooseberries.  Matthew Biggs mentions, (but cannot recommend!), that a sprayed solution of bicarb (5g per litre) can be used to control the mildew.

DSC_0054I have also been washing the leaves of the citrus – Calamondin, Citrus x microcarpa, with a mild soapy solution.  The orange has taken a hit of scale.   Scale insects suck sap and secrete honeydew which in turn encourages sooty mould. It’s easy to control – just fiddly to treat all the leaves.  I shall pot on my citrus; they are hungry plants, so a refresh of the compost, (JI no. 3 plus grit), is timely.  I will also keep feeding the plants every week  throughout the summer. 

Pestilence begone!