Every year we stump a block of trees. We rotate through three blocks, where one block is taken out each year. That takes 1/3 of our farm out of fruit production for a year. We started doing this to control for coffee berry borer (CBB) beetle. And when coffee leaf rust (CLR) made its disastrous appearance in 2020, this style of pruning was the recommended way to handle rust, as well.
Stumping was just done last week. The photos taken below were taken the day after. Now the piles of removed branches are brown, awaiting chipping later this week. Though in the 2024 block to be stumped, the young trees planted in 2021 were not stumped. Most of them are not thriving. Many got bashed around by pigs within months of being planted, and then we had some critical dry months.
The remaining trees are flowering again, just a couple of weeks since the last round. This time it’s from rain we received in the beginning of February.
There’s a pruning workshop that the University of Hawaii, College of Tropical Agriculture and Human Resources (CTAHR) extension will offer next week. I’ve attended a few times. I like seeing/hearing about the experiments they do in their demonstration field. They’ve stumped various trees in February, March, April, May, November, and December of 2022. And they’ve stumped in January, February, March, and May of 2023. All of us farmers can learn from their experience. Stumping is pretty tough on the trees. What’s the effect months/years later of pruning as the days get longer, the soil warmer, and with differences in rainfall? When I look at rainfall bar charts from the past several years, it’s difficult to see much of a consistent pattern. You don’t want to stump before, e.g., a weeks-long period with little or no rain. But who can really predict whether that will likely happen or not?
Segueing to today’s other chosen topic … I once visited another small coffee farm, about the size of ours. The farmer said his short term vacation rental made way more money than his coffee (no surprise there). And he was considering changing his crop from coffee to avocados. That was before avocado lace bug.
Avocado lace bug was another pest to arrive in 2020, the same year as COVID, the same year that coffee leaf rust arrived. When a tree is heavily infested, it’ll drop its leaves. It is heartbreaking to see large, mature avocado trees without any leaves and avocados hanging like ornaments. You might see something like that with persimmons. Pretty orange fruit hanging from a tree with few or no leaves. This is not so for avocados, though. The fruit, which would normally develop under leaf cover, often get sunburned, which affects quality.
One of the techniques to deal with lace bug is pruning, but we don’t want to prune until we hopefully get our first avocados. Last year we pruned too early and never got fruit. We have done some treatment by spraying the trunk, branches, and under the leaves with insecticidal soap and oil. And it has to be done 2-3x, a week apart, to be sure to get the eggs.
We planted just two avocado trees in February 2021, Yamagata and Kahalu’u. We have other avocados or access to our neighbor’s avocados, but they are of unknown variety. Different areas on our farm have different depths of soil and blue rock (dense and hard). Avocado varieties can be vigorous, moderate, or slow growers. And then individual specimens of a given variety might thrive better than others. The Yamagata tree is still quite small and has dropped its leaves two times due to lace bug already, but the tree is still alive.
The Kahalu’u tree is a vigorous grower. Sometimes it seems like it outgrows lace bug. It’ll drop leaves, but then new leaves grow back. In the photo of the whole Kahalu’u tree below, the lighter colored branch in the foreground had dropped all its leaves, but it grew flowers and new leaves. The taller, darker green branches are much healthier and are farther behind in flower development.