Garden Guy: Various factors influence tree’s fruit growth


We have a house in upper Hawaiian Paradise Park and plan on retiring there next year. We have several citrus and plum trees, a fig tree, and a longon tree that have been planted, some for about five years and some for just one year.

We had been using long-acting citrus spikes, but this year started having tenants fertilize every other month with organic dry chicken manure. All the trees are much smaller than they should be and are not bearing fruit. We know we need to soil test. What else can we do to get fruit on the trees next year?

Once we retire there, your classes will be a must! Thanks for the help! N. and K.

First let me say, for informational purposes, that a soil analysis is best taken before the trees are planted. This is because some additives, such as phosphates fertilizers and lime, are not readily leeched, or transported, by soil water down to the roots of the tree. It is, therefore, best to physically incorporate these materials into the soil before the plants are put into the ground.

Poor growth of the fruit trees results from a variety of factors: disease, poor soil conditions, pest invasions and nutritional imbalances. But one important subject that is often forgotten by absentees is the water issue. It is often thought, “If it’s Hawaii, there must be plenty of water!” True, there are numerous times when the rainfall is sufficient for good tree growth. But conditions also exist where soil

is limited or nonexistent and unless rainfall occurs almost daily, the soil will not be able to store enough water for good growth.

The most deceiving condition is lava rock with only an inch or so of soil on top. Under this situation, water will only be

available for merely a couple of days. Mulching the trees will help take the tree through the drought period.

I would also strongly suggest viting the the College of Tropical Agriculture and Human Resources website and read some of the many

publications on fruit trees and other gardening subjects.

Finally, for the sake of good will with your tenants, it should be sufficient to apply the chicken manure two times a year.

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When purchasing lures for the pesky fruit flies, unfortunately, one size does not fit all.There are different lures (attractants) for the different species of fruit fly.

Methyl eugenol is an excellent lure for the oriental fruit fly; trimedlure is used to attract the Mediterranean fruit fly; and the latilure is used for the solanaceous fruit fly, and cuelure works reasonably well for the melon fly.

The Knowledge Master section of the CTAHR website will give you excellent, detailed information on the various species of fruit fly: their host, distribution, damage, biology and management. http://www.extento.hawaii.edu/kbase/crop/type/fruitfly.htm.

In the field, these lures can last for weeks to months. It is the males that are attracted to them. The idea is to saturate a given area with the lures which will then trap the flies or kill them with an added toxicant.

For purchasing lures, the UH Master Gardeners are active at community events demonstrating the use of the fruit fly traps. You can call the office for information about the next event, or stop there and ask to see one of the homemade traps, 875 Komohana St., Hilo; Monday, Tuesday or Friday, 9 a.m.-noon, or call (808) 981-5199.

Hilo resident Nick Sakovich is a professor emeritus of the University of California. He has worked in the field of agriculture for 30 years. Email your questions to Sakovich at askthegardenguy@earthlink.net. Also, visit his website at www.gardenguyhawaii.com.

 

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