Sunday | October 22, 2017
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Yams and sweet potatoes aren’t the same after all

When is a yam a sweet potato?

While enjoying the traditional Thanksgiving dinner, many may wonder what’s the difference between yams and sweet potatoes. All right, maybe not many. But what are the differences, or are they the same thing with a different label? Many years ago, orange-colored sweet potatoes were introduced to the Southern United States. In an effort to distinguish these from the traditional white-fleshed potato, producers called them yams, which is the Anglicize African word, nyami. Today, most of the starchy tubers consumed in the U.S. and labeled as yams are in reality sweet potatoes. Yams and sweet potatoes are not the same; in fact, they are quite different from each other.

As far as botanical order is concerned, they are at opposite ends. The sweet potato is a dicot in the morning glory family, while yams are a monocot, closely related to grasses. The sweet potato, whose sweet and moist flesh varies in color from white to yellow and orange, is native to South America; the skin is typically smooth.

Yams, on the other hand, are dry and starchy and rather bland, yellow or purple in color, and the skin is rough and a bit shaggy. Yams are native to North Africa and Asia. They range in size from that of a small potato up to 150 lbs. Yams are a primary agricultural crop in for the complete article on citrus scab.

How do I get rid of leafminers? I have already cut off the infected leaves. Any organic solution?

Also, I live 1 mile mauka of the hospital at an elevation of 800 feet. Is it possible to grow mamaki at this level? I would like to promote butterflies in my garden. Do you know where I can purchase a plant?

Thank you very much. — M.A., Hilo

Regarding leafminer, for the homeowner there really isn’t a good solution for their control.

The good news, however, is that in most cases, no treatment is necessary because of biological control. See my website and search leafminer; there you can read in detail about leafminer. Mamakai will grow at your elevation. Periodically I have seen them at Paradise Plants in Hilo and other local gardening stores.

You can also contact Gwendylon at, she is an avid butterfly advocate and may help you in that regard.

Aloha, Nick, thanks for your column about lilikoi. I think the butterfly/caterpillar explains why I sometimes find larvae inside ripe fruit. On my vines there was a spiny little caterpillar eating into one of the flower buds, and I’m thinking he moved in(?) or laid eggs inside the developing fruit, which nourished the little buggers as they grew. Any truth to this theory? Sorry, but no.

A couple of years ago I lived in N. Kohala and there was a very nasty caterpillar, stinging nettle by name, that really chewed up a young vine I was nurturing. It gave me a very itchy, scabby rash when I brushed up against it unknowingly, and it looked just like the ones I’m finding now. I sure HOPE they are NOT the stinging nettle. Most likely not.

You are dealing with three different insect pests here.

1. The caterpillar feeding on the lilikoi leaves is the immature stage of the passion vine butterfly as discussed in a previous column. They do have spines, but not irritating like the stinging nettle caterpillar.

2. The small worms inside some of the fruit are probably the larvae or immature stage of fruitflies — either the melon fruitfly or the Oriental fruitfly. Adult fruitflies lay their eggs in young, tender fruit and cause them to shrivel and fall. Note: Passionfruit (lilikoi) is not commonly attacked by fruitfly species.

3. The stinging nettle caterpillar does indeed have spines which can cause itching and painful welts. For more detailed information on any of these pests, see the website at and search for passion vine butterfly, fruitflies and stinging nettle caterpillar.

Master Gardener Classes

The University of Hawaii Master Gardener Program will start a new 2013 class in February.

The Master Gardener Program trains individuals in science based gardening. Upon completion of the program, trainees volunteer to work on community projects and to help home gardeners with their gardening questions.

Classes will be held in Hilo from 9 a.m.-12 p.m. Tuesdays and Thursdays, Feb. 26-April 11. There is a class fee of $105. Application deadline is Dec. 15.

Contact Andrew Kawabata at 969-8251 or email him

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


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