Archive for the 'Pests & Diseases' Category

box

I knew it was a risk when I planted it but the Box hedging has started to succumb to Box Blight already. I’ve replaced two of the bushes because they were displaying the tell-tale orange hue. I thought I would nip it in the bud early and see if I can stop the spread. Also the cuttings that I took last summer are starting to grow in the greenhouse so pretty soon I should have my own bushes ready to replace any more that are affected.

I know it’s crazy to plant Box now that blight is so wide-spread. And in such a wet climate too! It’s just that I love the ‘box edged’ look so much. I’m willing to fight.

mtp

How to Spot Curly-Top Virus

curlytop

Until a few weeks ago I had never heard of Tomato Curly Top Virus. I was manning the phones at the Master Gardener clinic when during a quiet spell my fellow volunteer pulled out a bag with a sick-looking Tomato plant in it. She said it was her neighbour’s plant and she’d brought it in to identify the cause of its demise.

It did look sick. The top leaves were twisted, cupped and rolled. Significantly, the leaves were not wilted but they did have a strange purple hue on their underside. It looked like it had been accidentally sprayed with something nasty. But it hadn’t – after much research we figured out it had Tomato Curly-Top Virus.

The virus is transported by the Beet leafhopper, which is prevalent in the US, Mexico and Mediterranean areas (not generally in the UK unless there is very dry spell). Leafhoppers don’t generally feed on Tomatoes but the virus is acquired from infected plants (usually crops) nearby and then transmitted to the Tomato while the leafhopper is sampling the plant.

There is no treatment for Curly Top Virus. Once transmitted the virus takes over the Tomato plant and it will not set new fruit after infection.

It’s also really difficult to avoid Curly Top Virus as there are currently no resistant varieties of Tomato. Take heart though, in most gardens its occurrence is an isolated problem. If you do find that you have a chronic problem, good ole row-cover or horticultural fleece will protect your plants.

mtp

Attracting Beneficial Insects

mesclun_2

My Mesclun Lettuce mix (which includes Pak Choi, Mizuna, Mibuna and Mustard) went to seed pretty quick in the hot weather but instead of pulling it I let it flower. These bright yellow flowers are from the Mizuna in the mix. The flower stalks are amazingly tall and stay upright. And they attract a wonderful amount of beneficial insects like hover flies, ladybirds, lacewings, bees and other pollinators.

mesclun_1

Getting the beneficial insects into the kitchen garden is the difficult bit. Once they are here they seek out aphids, mealy bugs and mites by themselves. It can only be a good thing, right? And the yellow flowers add a great backdrop to the rows of Lettuces below.

mtp

Onion Fly

onionfly_1

One of my Shallots started to wilt around two weeks ago. The foliage turned an unusual light green colour and started to keel over. Over time it just continued getting worse and worse with no sign of recovery and so I thought it was about time to find out what was wrong.

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As you can see here it was the only one of the bulbs to be affected in the row.

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When I dug up the plant the culprit was clear; Onion Fly. The base of the Onion is beginning to rot and you can see tiny maggots (larvae) wriggling out. These eat the onion and then eventually turn into Onion flies.

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You can see how tiny the larvae is in this photo. So what’s to be done? Nothing for this plant. I had to dig it up and put it in the bin. For the others I can just hope that this was an isolated case. I will be digging the soil over to see if I can see any other larvae. But they are so tiny it’s unlikely I will see them. I could use row cover or horticultural fleece over the plants to stop more females laying eggs.

Next year however I’ll be rotating my Onion bed to another part of the garden just in case it’s a problem with that particular bed. Apparently, putting sets in later in the season helps too as you can miss the first wave of flies. There are also nematodes that you can buy that will deal with this situation.

But… as I’m not a farmer and my livelihood doesn’t depend on my Onion crop, I’ll probably just hope that I can harvest most of my Onions and be happy with that.

mtp

Root Weevil Larvae

Vineweevil

I found some of these lovely little grubs in a potted plant that I bought at the nursery. I looked them up in my insect field guide, since I didn’t want to squash them if they were beneficial insects. They’re not. They’re the larvae of the Vine Weevil (from the largerRoot Weevil family) they feed on a plant’s roots and then hatch into those brown/black beetlelike bugs that eat notches out of the leaves on Broadbeans, Rhodedendrons and countless other things. So they got squished. And you should do the same if you see them too.

Root weevils in general can do a lot of damage to leaves. They tend to come out at night so the best way to catch them is to collect them in the evening in a jar. If you dig around the bottom of the plant too you might find some of the grubs above. These are best dealt with in the Autumn.

slugs

There’s not much going on in my garden right now so I’ll carry on with my ‘Master Gardener‘ series.

This week on the course we had a lunchtime speaker come in to talk about slugs and snails. Part of the talk was about how to reduce their numbers in the garden but mostly it was about getting to know slugs and snails better. Because the more you know about something, the better your chances of fighting it. So here goes:

There are lots of types of slugs. The larger ones may look mean but in truth it’s the smallest ones that tend to do the most damage.

If you see a leaf with a ragged-edged hole it’s most likely slug damage. If you see a leaf with a smooth-edged hole it’s most likely a caterpillar or vine weevil . Slugs eat with a dragging motion, hence the ragged edges.

Slugs are hermaphrodites. When they mate both slugs become pregnant. A slug can produce 500 eggs per season.

Their eggs are clear and gradually go opaque. The slugs keep the eggs inside them until there is 25 per cent moisture. Then they lay them.

Slugs avoid eating:
Ferns, Ivy, Sweet Woodruff and Foxgloves (among others)

Slugs love eating:
Hostas (but not the blue, quilted kind for some reason)
Lettuce, Daffodils, Lilies, Strawberries and Primroses (among others!)

They live under rocks, mulch and anywhere it’s moist.

They like to eat at night, or when it’s wet.

Defences include:
Barriers like copper strips, coffee grounds, egg shells.
Salt.
Citrus or Melon halves then trap them.
Beer traps.
Lettuce under a board then trap them.
Nematodes watered into the soil.

Repellants include:
Garlic, Cinnamon, Copper

Slug bait is exactly what it says it is, bait! The slugs move towards it so don’t put it all near your plants. Put it between their home and your plants. In other words find out where they live!

Research shows that it’s best to bait every two weeks because slugs do have some form of memory and can remember where you put it.

Slugs can see about six feet, and they can smell about three feet.

Chances are you’re using too much bait. You only need a light sprinkle. Because they are attracted to it they will seek it out.

And remember slug bait is toxic so only use it as a last resort and away from children, pets and ideally birds.

mtp

Epic Elm Tree

I’m not really a tree person. I like trees. I like to look at trees. I’m always happy that trees are there but I don’t think I’m the kind of person who would say, “Let’s plant an Elm tree.” I might say that about an Apple tree or a Pear tree. And infact I did say that about a Medlar tree just the other day. But when it comes to those kinds of trees that you really should be able to recognise the leaves of… hmm no.

So, the fact that I have inherited a garden with the most beautiful, epic and very, very tall Elm tree in it is a bit unsettling. I’m beginning to like it though. The squirrels love it. They climb up to the most wobbly of highest branches and throw things down. At me? Maybe.

According to some neighbours there is a raccoon family that come back every year to the tree to raise their babies. Raccoons are new to me and so I was looking forward to that.

Yes I was getting very attached to my epic Elm tree until the parks department sent me a letter that said the tree might have Dutch Elm disease and that if it did then it would have to come down.

All of a sudden, after having no feelings what so ever for this tree, I felt sad. I tried to imagine the garden without the tree and realised that it would make a stark difference to just about everything. And what about the raccoons!

Anyway, the tree was tested for the disease and the first results came back negative. After the second pass we’ll know for sure. But in the meantime I think I might just give it some water.

mtp

Cabbage White Caterpillars

This is what Cabbage White caterpillars look like when left to their own devices. I thought I had squished all of the eggs on my young Cabbages, Broccoli and Kale plants, but no. Apparently, this little clutch of siblings had evaded my thumb. I found them munching through this leaf and promptly nipped it off.

The thing is when they get to the moving stage I just can’t kill them. They’re too, you know, alive. So I put the whole leaf, caterpillars and all, in the compost bin. I’m not sure what will happen to them in there but at least they will have something to eat, if not anywhere to fly to. Oh well.

mtp

Orange Spot on Pear Leaf

While inspecting my three Pears dangling from my Pear trees I found these, nasty-looking, day-glow spots on some of the leaves. Yuk! Apparently it’s Pear rust and is a fungal disease that affects Pears and Junipers. Infact, the spores need a Juniper to over-winter on!

I don’t own a Juniper bush! One of my sneaky little neighbours must be harbouring one. Humph.

I need to snip off the infected leaves on my Pear trees and prune infected branches off the Juniper otherwise the problem will keep coming back. Do you think they would mind if I hopped over the fence at midnight and did a little free pruning? No, I thought not.

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It’s about this time of year that I start to fuss and worry about blight on my Tomatoes. I’ve never really been able to relax since The Year the Tomatoes Died. So I thought I would re-publish this little article that I wrote last year for the Guardian Gardening blog. I will be doing all of this again this year, come rain or shine :)

When I first starting vegetable gardening in 2005 growing Tomatoes was a doddle, a breeze. Just bung in the plants, water them a bit, feed them a bit and ta-da! right on que at the end of August you’d be eating your own home-grown tommies.

Not anymore. Over the last few years, our summers have been, well, disappointing. And if we’re deluged in rain again this year it means one thing; that growing outdoor Tomatoes in the UK will be more of a battle with wind and rain in an effort to avoid the dreaded…gulp… blight.

As most will know, Tomato blight is a nasty disease that starts with small brown patches on stalks and leaves but soon progresses to the fruits.

If I had a greenhouse I’d take my Tomatoes under cover. But since I don’t have that option (and frankly the thought of ‘not’ growing Tomatoes makes me feel a little nauseous) then there’s only one thing for it – to fight.

Here’s my plan.

  1. Grow (or buy) vigorous, healthy plants.
  2. Don’t plant Tomatoes in the same spot as last year.
  3. Plant disease-resistant varieties (Ferline, for example)
  4. Remove the bottom leaves up to the first truss of fruits to avoid splash back
  5. Remove and destroy all plant waste after the growing season
  6. Avoid watering on to the leaves. Water directly to the roots and don’t handle plants when the vines are wet.
  7. Control weeds in and around the plants. Weeds serve as hosts for insects and disease.
  8. Control pests (particularly aphids) which may transmit disease from plant to plant.
  9. Remove plants as soon as the tell-tale brown patches are seen. Wash hands and tools with a detergent after handling affected plants.
  10. Choose a sunny location and provide a removable rain cover if possible.
  11. Pray (or at least ask the rain gods to take pity on me).

So there you have it my 10 – err 11 point plan. If anyone has any more suggestions then please post them in the comments. When fighting Mother Nature you need all the weapons you can get.

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