Friday, 18 December 2015

Problem Area - Plant Pests ... Lily Beetle!

Good Morning!
Welcome to my next post related to Problem Areas. Currently I am focusing on Pests!
What exactly is a Plant Pest? 
A Plant Pest gains it's nutritional requirements from the host plant it feeds upon. 
There are various ways which it can gain it's sustenance but broadly speaking it either eats or sucks a plant's sap.
It's a good idea to take note of a pests life cycle as they are more vulnerable at certain stages.

As the name suggests these are common pests to Lillies and Fritillaries and are distinguishable by their red colouring. As you can see from my photo below the adults can be found on and near other plants but it's only on Lillies and Fritillaries that their eggs are laid and grubs develop upon.

Lily Beetles or Red Lily Beetles as there otherwise known overwinter as adults under the soil, leaves and other sheltered places. This can be anywhere and not always near the plants that they favour. The beetles emerge on sunny days during March / April time when they start to look for foliage on host plants. Adults lay their eggs on the underside of leaves from April to mid - summer which hatch and the larvae then feeds on the foliage. When fully fed the larvae will go under the soil to pupate and emerge as adults during the summer. There is only one generation per year so unlike other pests these new adults will not mate until the following year.

Foliage on Lillies and Fritillaries is eaten away by the grubs hatched from eggs on the underside of leaves. The eggs are in clusters of orange/red and are sausage shaped, the larvae are about 6-8mm long and reddish brown, usually covered in their own black excrement. These grubs usually graze on the underside of leaves, resulting in dry white / brown patches and older grubs can devour whole leaves starting at the tips working back towards the stem.
Adults make rounded holes in the leaves when feeding and will also feed on petals & seed pods.
These attacks in Summer can lead to undersize bulbs developing which can hinder flowering the following year.

Lily Beetle Larvae Photo from Google.

Adult Lily Beetle Photo from Google.

If like me you like to garden Organically there are a few things you can do -
* Pick off and remove the pests as soon as you spot them.
If you only grow a few of these plants start inspecting them regularly from March onwards for any signs of the pest.
* Grow a variety that is claimed to be Lily Beetle tolerant -
Lillium (Lily 'Defender Pink').

There is also Chemical control available however please note that if you choose to use this please avoid spraying on plants in flower to avoid harming any innocent pollinating insects.
These products are also usually only beneficial on the young newly hatched larvae rather than the adults.

I hope you have found this interesting and helpful if any of you come across this particular pest!

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