Still in Pestville today. Just hanging out, getting to know which evil characters to look out for.
Glasshouse Red Spider Mite
Niche opportunities exist within the Red Spider Mite franchise. Other operators specialise in Box, Conifers and Fruit trees. But it’s the glasshouse variety, the one with sap sucking designs on greenhouse tomato plants which concerns us.
Another sap sucker. More mite than a spider, though it does weave miniature webs, which with a bad infestation, stretch across between leaves and stems.
Miniature, because it’s tiny. Less than 1mm long. What it lacks in size, it makes up in numbers, both of its kind and in eggs. Its invasion can last from mid spring to late summer.
All that collective sap sucking results in the life being sucked dry out of the leaves which end up with white/yellow mottling, losing their green colour, curling up at the edges, drying up, giving up and falling off.
- Chemical control
Too long being blasted has rendered them blasé and resistant - Biological control
However they need to beware the Predatory mite; Phytoseiulus Persimilis which eats Red Spider Mites for breakfast, lunch and tea and hopefully disregards rules about not eating between meals - Cultural control
They like their greenhouse nice and warm and dry so a blast of sprayed water or damping down, to up the humidity should fix that.
If the plants are in pots they could be moved out of doors and if at the early stages of infestation affected foliage removed
However if it’s bad, the plant won’t recover in which case its best to watch the whole lot, plant and mite, go up in flames.
Other sap suckers which are not so likely but useful to know about are:
- Glasshouse Leafhopper whose sap sucking antics create coarse, pale spots on the leaves
- Southern Green Shield Bug. Invades from southern Europe and hasn’t made many inroads into the UK yet. Plus it doesn’t arrive until late summer/early autumn so toward s the end of the main tomato season
And then a couple of other creepy crawlies with nothing but eating on their tiny minds:
Tomato Moth – or more specifically its caterpillar.
The moth is small, brown and goes by the less drab name of Lacanobia Oleracea. Its larvae start by nibbling away at the underside of the leaf and then the caterpillar gets into full swing eating clean through the leaf and making holey inroads into the tomato fruit
- Chemical Control
Pyrethrum or Bifenthrin (synthetic pyrethrin compound) on the larvae - Cultural Control
Finding all those caterpillars and dispatching by hand. And swatting and squashing the moth if spotted.
Vine Weevils
Again, the offspring are the biggest problem. The adults eat leaves, working their way round the edge of the leaf like a misshapen hole puncher but the larvae which are hidden in the soil munch their way through a plants roots. The plant wilts and when the roots are eventually severed, dies. Plants in containers are especially vulnerable However I think the timing all of this underground destruction means main crop tomatoes may escape, as although the Vine Weevil lays it eggs earlier, the larvae don’t get going till earlyautumn.
- Chemical control
Pah ! - Biological control
The pathogenic nematode, Heterorhabditis ssp. and parasitic eelwormSteinernema kraussei nematode
Frogs, toads and hedgehogs are also partial to a Vine Weevil - Cultural control
To get rid of the eggs and break the cycle, remove all the affected soil and burn
So when it comes to small, insect like pests, likely to upset the UK tomato cart, all the above with yesterdays’ Aphids and Greenhouse Whitefly complete the cast.
Lets hope this summer they remain in the Green Room rather than making it out to the Green House.
