Need a cheaper insecticide

I've got some boxwoods I have to protect from miner bugs every spring, and right about now is time to do the annual insecticide drench, and lo and behold the stuff has doubled in price just like everything else. I'll include a pic of what I've used up til now. It used to be a concentrate that you watered down and applied, but now the new and improved version is undiluted and very $$. The main ingredient is 1.47% imidacloprid after it's diluted.

Any suggestions for a cheaper insecticide alternative with the same active ingredient?

Thanks!

 

The best insecticide is a diverse garden. Everything gets eaten by something else, unless the something else is missing, because it's been poisoned.

 

Hello bradleyheathhays, welcome to GC Are you sure that what is attacking your Box plants is leaf-miner and not Box caterpillar? Have a close look at the leaves for signs of webbing and tiny caterpillars rolled up in the leaves. The two current scourges of Box here are Box moth and a fungus disease. For the former, there is a very effective treatment using a bacterium, Bacillus thuringiensis. A powder that you mix with water and spray on as a preventative or cure. The bacteria only targets caterpillars and is harmless to other insects and humans. I'm afraid I don't know the brand names that it is sold under in UK, but it might be worth looking out for in a garden centre near you? It's one of the few garden-related products over here that isn't expensive!

 

@bradleyheathhays If you could fill in the location box it would help.
RHS advice
Box leaf-mining gall midge
The box leaf-mining gall midge, Monarthropalpus flavus, is uncommon in Britain but occasionally feeding damage is observed. This tiny fly deposits its eggs in the new leaves during late April - May. The larvae feed inside the foliage, causing a yellowish discolouration on the upper leaf surface. The lower leaf surface develops a slight swelling in the area affected by the larva's feeding. The yellow larvae are up to 3mm long and they feed inside the leaves during summer – winter before pupating within the mines in spring. Several mines can develop in a leaf and heavily damaged ones often drop off.

Whilst the damage caused can be unsightly it rarely affects the vigour of plants and it can usually be tolerated.

You may find these web sites helpful.
Boxwood Leafminer — NewGen® Boxwood
Managing Pests in Gardens: Trees and Shrubs: Invertebrates: Boxwood Leafminer—UC IPM
Boxwood leafminer

Apparently there are resistant varieties that may be worth investing in an would be an environmentally friendly approach.
In the EU and UK imidacloprid and other neonicitinoids are restricted in use due to effects on pollinators especially bees.

 

Ah...missed the dollar signs It makes a change to hear about a pest we haven't got here

 

I only twigged when I googled it and read Wiki entry about it.

 

I use a solution of 5 ml of Neem oil and 2 ml of washing-up liquid in a litre of water.

 

This will work for pests on the leaf surface where it can come into contact with the pest, but things like leaf miners and bud mites etc burrow into the plant and really need a systemic insecticide to get at them.

 

The thing is are we trying to kill the adult or the larvae.
It seems a bit early to me to be applying anything.

 

That is applied, in the winter/early spring to kill the larva.

 

The larvae is inside the leaf so contact poisons will not touch them.

 

Thanks for all the advice everyone!