For several years there has been something on mango trees killing some of the new soft shoots. This year it's been on almost all trees, continuing for every new flush.

 

 

There are small holes around the shoot evenly spaced. And a few other holes further out. It's not stem borers when I never find any larvae inside. I have stem borers too but they only make one hole. There could be a sap sucking insect walking around the shoot making them? Must be during night when I never seen any bugs in daytime. They do much harm as the trees struggle to grow and get cut back all the time. Haven't done any spraying of wood vinegar and soap this year when most trees are doing OK without it.

Anyone got a suggestion what it could be? Might have to spend some nights with a headlamp among the trees...

 

 

https://plantwiseplusknowledgebank.org/doi/epdf/10.1079/pwkb.20187800556
 

6 hours ago, degrub said:

https://plantwiseplusknowledgebank.org/doi/epdf/10.1079/pwkb.20187800556
 

Thanks, I have half of what's on that page. But noting like this.

I haven't seen that specific pest damage, but the hole pattern looks like weevil damage. More important than what exact pest is causing it, is why is it there? 

 

Plant pests and diseases are many, and there are new ones that are hard to keep up with. If its not one thing it will be another, as long as the  trees are physiologically weak and have not developed natural resistance. 

 

The foliage shown in the photos is chlorotic (pale, yellowed), most likely from nutrient deficiencies and/or excessive pruning with heading cuts. Use thinning cuts/drop-crotching and don't over-prune, which creates excessive vegetative growth that is attractive to pests. High NPK chemical fertilizer also creates biochemistry that is a pest magnet. 

 

Create good growing condtions, build soil organic matter content and a healthy soil microbiome, soil surface shading, mulching, cover cropping, and attend to soil fertility and water management as the first line of defense. Building the tree's natural resistance to pests and disease, protecting and enhancing the soil and foliar biome and beneficials should always be the focus for optimum tree heath care.  Look to regenerative agriculture and soil food web principles. Use biologicals and not harsh chemicals. 

 

 

I did find them on a mango tree daytime. A whole bunch of them on a new shoot. About 8 mm long bright shining blue with club antennas. Didn't get any useful picture as it was windy that day.

 

I'm practising permaculture and use only manure, compost and plenty of mulch. The reason for sad looking trees is that those bugs eat away every new shoot so trees have only old leafs. The few mangos they haven't found (yet) are looking healthy.

 

If I see them again and get a good picture I will post it.

I think you have it backwards. The reason for sad looking trees and the reason that the insect pests are attracted to the trees is inadequate plant nutrition, and often poor growing conditions and water managment. Physiological weakening from drought stress is an invitation to many plant pests.

 

Permacuture, manure, compost and mulch do not necessarily cover all the bases in builiding soil health, plant nutrition and natural resistance to pests. In fact manure, too much manure, especially non-aged/non-composted manure can have detrimental effects on the beneficial soil biology and nutrient cycling.