Lemon tree borers.

[Lungstib]

My wife's father planted some lemon trees when they were quite rare, then she 'air layered' some more from the existing plants and finally acquired extra from a neighbor who started growing lemons and then switched to oranges when the plants were only 2 ft tall. With aprox 100 trees we expected to send fruit to the local market and restaurants to help our small income. What we hadn't reckoned on was infestations of borer bugs. Last year it looked like an army of workmen had gone around drilling 3mm holes in the lemon tree trunks and branches. This year is even worse. By the time this wet season is over ( and thats when the activity is greatest) I reckon we could lose 30 young trees which haven't yet even given fruit. Being concerned with chemicals we haven't sprayed our trees as the other local farmers have but here lies the problem with ridding the country of chlorpyrifos without having reasonably priced alternatives. Pyrethrum in NZ is $35 for a small bottle. Being elderly and not professional it is unlikely we will do anymore than cut out the dead branches and plant more mango's which we 'rent' out to a younger, fitter neighbor. I fully understand people not wanting chemicals in their food but bug infestations like this will mean no lemons rather than tainted ones. I feel for the farmers, its not easy.

 

[hank2800]

you should spray these heavily and soak the surrounding ground with a form of Cypermethrin, Chlopyrifos as you mentioned is generally what I find around Chiang mai ask your garden center closest what they recommend and they may have something more mildly % concentrated that you could use longer term . Cypermethrin would be considered moderate as far as the dreaded insecticides go especially in Thailand (I haven't seen  Paraquat in Canada for 20 years), and there are more potent sprays if you like  (I can't wait to see the replies to that statement) but you need to stop these borers ASAP, we lost a lot of Coffee trees around Chiang mai to them and Unless you accept having these chopped in half every year you'll need to get some spraying started.(remove them or spray them  are   your choices or go to Mangos like you said) Organic sprays and their like will not hold up during rainy seasons for stem borers on this scale that you've described.Although  you don't want to spray,, If you can stop it this year,, next year you can try regular intervals of organic sprays to help keep them under control.by the sound of your post your neighbors are all spraying anyway so I don't know how "organically "isolated you still are, kind of like the organic rice farmer getting water from the canal that just went thru 10 non organic neighbors fields, but I understand your concerns good luck!