An environmentally-friendly way of getting rid of stink bugs is to use a stick to knock them into a container with some methylated spirits in the bottom of it, so that you don’t have to come in direct contact with these smelly bugs that change colour from green to orange to brown-black as they grow.
However, a reader e-mailed me this week about his problem with lots of stink bugs on his orange tree that is too tall to use this method, and he wanted to know if he could spray the tree with metho, instead.
Spraying the bugs with methylated spirits would only further damage the tree. If you also have a tree affected by bronze orange bugs (stink bugs), these bugs are a sign that a tree is very under-nourished. It is probably extremely water-stressed, as plants can’t absorb nutrients from soil if it is not damp enough for the minerals to become water-soluble. Give the soil around the affected tree a thorough watering, then give it an application of complete organic fertiliser and then water in some organic seaweed tea. You haven’t said which climate area you live in. If you live in an area where water shortages are common, keep the tree pruned to a size where it can remain healthy on the amount of water that you and nature can provide.
Bronze orange bugs or stink bugs and harlequin bugs are sap sucking pests that can do a lot of damage to stressed citrus trees. Spined citrus bugs suck sap from fruit. Before dealing with these bugs, you need to don old clothes, sturdy shoes, gloves and goggles or sunglasses as bronze orange bugs eject a corrosive fluid with a vile smell when they are threatened.
Young bugs tend to cluster under the lower leaves of the trees and are easy to get at, but if trees are too large for knocking them into a tin, spread some large sheets of plastic under the tree, then use a broom stick or long pole to give the foliage a good shake and, when they drop to the ground, either squash them, or gather up the plastic and slide them into a large container with a suitable pest treatment in the bottom.
Organic-registered products such as Natrasoap (not ordinary soaps or detergents) or Eco-oil will kill these pests but they should not be used on heat-stressed or water stressed plants, or in high temperatures. However, either of these products can be used to spray stink bugs when they shelter around the base of the tree on hot days. Harlequin bugs like to shelter in weeds, and they can be sprayed where they are hiding. Get rid of weeds, particularly along fence lines to prevent re-infestation.
However, the best way to avoid these horrible pests is to take good care of your citrus trees.