Attack of the emerald beetles

[Stevemercer]

I'm seeking advice on the best way to control these beetles. They can strip the new growth off a young mango is just a few hours. I currently spray with an insecticide labelled 'carbosulphan' (I suspect this is not the correct name, but I cannot read the Thai). It seems to work OK, but I'm wondering if there is something better to control the beetles? I've put in about 250 young trees and it is a bit of a battle keeping the insects at bay.

[soidog2]

Cypermethrin will work.

Applied properly; the bugs will gone.

Please use protection, get a Thai reader to tell you the indicated dosage for mango.

[BSJ]

My wife uses 4 or 5 different products to kill insects. I can't tell you the Thai names but there is one for when the trees are flowering and the others you can use anytime. We get all sorts of bugs. All up 3 different types of caterpillar and 7 flying insects....plus ants. Ants get into the tree fairly quickly so you really need to do a weekly walk around. Not so bad with 250 trees....but a pain with 850!

[Stevemercer]

Thanks for your advice. I will try Cypermethrin next time.

My wife says not to use insecticides and to let everything achieve a 'natural balance'. I tell her that might work when the trees are more mature, but the saplings can get defoliated by insects quickly. I want to give them every change to grow quickly and not have the new growth always eaten.

[xen]

There is a real dilemma here. If you use the the poisons to kill your emerald beetles then you also harm, if not kill all your natural predators including bees and birds .

Relying on natural predators takes time and the Emerald Beetles as you call them (are they harlequin beetles?) will have done the damage . Plus if a lot of your neighbours are using heavy chemical control for insects and bugs then your efforts in using natural predators are in vain . The other thing to do is watch the area that the trees are in and look for them ,if possible in the pupal / cocoon/egg stage and take measures to control them then . (Integrated pest management)

Usually infestations of beetles or other pests indicate poor cultural practices - too much water/ not enough/water stress, poor drainage & compaction of soils , fertilizers used incorrectly, sometimes poor pruning and so on. I am not saying you are guilty of this but something to be aware of . I think you mentioned they are only young and as the trees establish they should become more resilient to insects and pests .

Hope this is of some assistance.

[Stevemercer]

Thanks very much for your advice. I wasn't sure of the name of the beetles (they are about 1.5 cm long with a vivid emerald carapace), but they probably are harlequin beetles.

I would prefer not to use insecticides and let things reach a natural balance. However, I am trying to re-establish trees and forest on filled land so the soil and drainage is not the best. I think I just need to help the saplings along for the first 1 - 3 years until they are tall and robust enough to look after themselves. The beetles previously left the mango trees alone, but for the first time are now decimating the new growth.

[luap]

if you are willing to use a backpack sprayer and spray a few trees a day, mix brown vinegar (white ok) with garlic (use blender to make liquid garlic)

than boil slowly so liquid won't block sprayer save all water, let it cool down

add to backpack sprayer with dish watering detergent and of course, water to fill backpack sprayer

vinegar and garlic will remove over 95% of bugs from any tree, the dishing washing detergent helps all ingredients to stick to leaves

[luap]

ops forget to mention, ratio doesn't matter, I use about 5 litre of vinegar and garlic water mixed, a few drops or more of dish washing liquid my 20 litre backpack, thank god it's battery powered

[Stevemercer]

Thanks for the advice. Much appreciated.

[BSJ]

The commercial vinegar solutions are so-so. The wife bought some last year but we have gone back to the nasty chemicals....that work!

But we use an airbus which is towed behind a tractor.

And your wife's natural balance theory is really heart warming but not going to do you much good. Even organic growers have to use something to kill the bugs.

[Stevemercer]

Yes, I think you would need something like that for 800 trees. Just spraying my 250 or so takes over an hour and carrying 20 L on my back with my pump sprayer is a bit of an effort. If I don't spray the new growth is just decimated. Since I started spraying about 12 months ago everything has shot up and the leaf mass has probably increased 10 fold or more.

Edited March 7, 2016 by Stevemercer

[canopy]

Even organic growers have to use something to kill the bugs.

I don't, but I must add a footnote everyone's situation is different and I don't have a field of saplings all being defoliated like the OP. A healthy tree is very good at defending itself naturally. I find mango trees to be very hardy among fruit tree species and various pests do little harm to the tree so I just let them be. However, wrapping each mango in a paper bag sold for this purpose is a must and then produces perfect, blemish free and bug free fruit. It's a relatively easy strategy and like Christmas time when it comes time to unwrap and see such wonderful, chemical free fruit. Very happy with this strategy.