Greener BeeGreen TipsHelen Yemm: easy climbers for a pergola, pests on fuchsia and hydrangea

A treatable fuchsia problem

Several years ago a very well-established fuchsia in my garden developed damage to leaf tips and emerging flower buds. Despite spraying and cutting it down severely the problem has persisted randomly – and not with all my fuchsias – each year since. I wondered if it might be fuchsia gall mite but was not aware this had arrived on the Isle of Man. Karen Rodger – via email

You will be relieved to read that your accompanying picture showed me that this is merely a severe infestation of capsid bugs which is, with a bit of persistence, treatable. Had it been fuchsia gall mite, which is far more disfiguring (pinkish yellow knobbly growths on shoot tips) you would be in far deeper water, for the mite is resistant to available insecticides.

Capsids are leggy, flightless insects that are seldom seen but leave nasty calling cards: they damage tiny patches of plant tissue as they suck sap from developing shoot tips of many plants and are particularly damaging to fuchsias, destroying flower buds before they are properly formed. You can successfully wage war on them as long as you are prepared to use systemic insecticides (Ultimate Bug Killer or Bug Clear). 

Spray your fuchsias preventively as they start to grow well in late April (to get the capsid advance guard) and then repeat the procedure again in July well before flowering starts, to knobble the second equally pesky generation.  

Capsids seem to dodge natural predators with great skill and hibernate in nearby bushes and hedgerows, so the war on them may have to become an annual event.

Hydrangea under attack

I have encountered a new pest on one of my hydrangeas: small white oblong caterpillars, apparently dead, have appeared on the backs of its leaves, which then turn rather brown and drop off. What are the beasts that are causing this destruction?  Anita Brown – via email

This is actually the work of the scale insect Pulvinaria hydrangeae, not caterpillars, and what you are actually seeing are their recently vacated egg cases. The newly hatched scales are tiny (less than 1mm long), yellowish and therefore hard to see.  They grow larger and browner as they mature, sucking sap from the plant which then flowers less well and starts to lose its leaves.

You will have a hard job controlling this pest without using systemic insecticides. There are various contact-only sprays that have to be repeatedly used. Systemic sprays thoughtfully used (in the evening when bees are abed) and carefully timed (taking into account the life cycle of each pest) are still, I maintain, the best way to combat sap-sucking garden baddies. But I’ll probably get mail for saying so…

 

Article source: http://www.telegraph.co.uk/gardening/problem-solving/helen-yemm-easy-climbers-pergola-pests-fuchsia-hydrangea/


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