Agriculture

Guava Power

Wednesday, May 4th, 2011

Community contributed by Glenn Teves, UH County Extension Agent

When it comes to an easy to grow fruit in Hawaii, guava tops them all. In fact, some consider it a weed that invades Hawaii forests, especially the strawberry guava, and natural enemies have been imported to bring it in check. Native from Southern Mexico to Central America, there are over 50 varieties of guava and they come in all shapes and sizes, from a cherry tomato almost to the size of softball. It first arrived in Hawaii in the early 1800’s, but is believed to have been grown by the Inca a couple thousand years ago.

And guava has got some power, and is often included among the superfruits along with wolf or gojiberry, elderberry, cranberry, pomegranate, blueberry, mangosteen, and noni due to its high antioxidant content. Just 100 grams of guava contains 700 mg of potassium, twice as much as banana, and 377 mg of Vitamin C, up to seven times more than a navel orange. There’s a lot of variability among cultivars in terms of nutrient and antioxidant content, but sour and darker red fruits are usually highest in both. Guava is relatively high in antioxidants including lycopene, polyphenols , and carotenoids. This is why guava is a must in every back yard. 

There are two main types of guava, processing types and dessert or sweet types. Processing types are higher in nutrients, and are preferred for making juice concentrate, jams and jellies, while dessert types are higher in sugars. Processing cultivars include Beaumont, the father of all processing guava in Hawaii, and its seedlings Ka Hua Kula (The Golden Egg) and Waiakea, improved selections utilized for guava production in the state. Dessert types are many, including Holmberg, Indonesian Seedless, and also Ruby X Supreme, an introduction from Florida. Others include an excellent small sweet guava from Singapore, introduced by Dr. Richard Hamilton, and fairly recent introductions of two large white fruited dessert selections from Taiwan with thick skin that tastes similar to Korean pears. The wild types are by far the most sour and also great for juice concentrate, and jams and jellies. In Taiwan, fruits are bagged on the tree when young, and sold for high price. Although seeds have some variability, this is an easy way to propagate them since grafting can be a challenge. The flesh can be white, pink, yellow, and red.

Guava has its share of pests including fruit flies, spiraling whiteflies, and coffee scales. Of these, fruit flies are the most destructive and can rot all the fruits. Oriental fruit flies are more of a problem in the lowlands, while the Mediterranean fruit flies are a problem in higher elevations such as Kualapuu and higher. Some of the lighter greenish-yellow cultivars are more susceptible to fruit fly damage because the insects sense a color change and will sting them before they’re mature. Using fruit fly traps, with methyl eugenol for the oriental fruit, and med lure for the Mediterranean fruit fly, supplemented with GF 120 fruit fly bait can help to bring fruit flies under control.  Trees can get of thirty feet tall, but pruning can keep the tree under control and fruits within picking distance.

Too much of a good thing is not good, and such is the case with guava, which can cause constipation. Used to your advantage, it can also cure diarrhea. Tips of the leaves are especially high in tannic acid and can be chewed to stop the flow of diarrhea. Thought to be Hawaiian folk medicine, this herbal medicine has been used by natives of Central and South America for centuries. 

This is one of these fruit where you don’t have to look far to find something very nutritious; just watch how many you eat. 

 

Sweet Onions

Wednesday, March 16th, 2011

Community Contributed by By Glenn I. Teves, County Extension Agent, UH CTAHR CES

Round onions are an important addition to many of our delicacies, but sweet onions are something special. Most onions are pungent, and even some purported to be ‘sweet’ are not. 

To grow sweet onions, it all starts with the right seed, and the ones synonymous with sweet onions are Granex and Grano. The Granex onion is derived from Bermuda onions which actually originated from Italy, and includes both a white and yellow selection. The Grano, also called Valencia Early Grano or Babosa originated from Valencia, Spain and matures later than the Bermuda onion.

In1933 Texas A&M University, working with the U.S. Department of Agriculture (USDA), started breeding sweet onions specifically for south Texas. These two onion lines became the backbone of the sweet onion breeding program, developing both the more flattened, early maturing Granex and the rounder, later maturing Grano.

In 1940, breeders stumbled upon a field of Granos that matured even earlier than the Bermudas, and this onion became the mother of all sweet onions, Texas Grano 502 or Texas Early Grano. Today, there are literally hundreds of granex and grano onion varieties including Yellow Granex, Tropic Ace, Texas Grano 1015Y, Sweet Vidalia, Granex 33, and even Early Texas Grano 502, all of which can be grown in Hawaii.

Round onions are classified as long-day, medium-day, and short-day, based on how they respond to day-length. Both short and intermediate-day onions grow in Hawaii. Short-day types will grow leaves when the days are short, and form a bulb when the days get longer. Our longest day is June 21 at 13 and a half hours, while our shortest day is Dec. 21 at 11 hours. Temperature and elevation can also affect bulbing by overriding the day length as in Kula, where onions can be grown over a longer season. Short-day onions are sweet due to a high sugar and water-content when grown in soil with a low sulfur content. A sulfur compound, pyruvic acid, is responsible for your tears; sweet onions don’t contain as much antioxidants as long-day onions.

Short-day onions mature in 150 days, and can be grown from seed or transplants. They should be sown from September to the end of March. The early part of the season is a gamble due to wet weather around harvest, but can reap major dividends since supplies are low and prices are high. Later in the season, sweet onions are being harvested world-wide, and commodity prices are down, but innovative marketing using the Hawaii name can reap dividends as well. Intermediate-day onions can be sown even later and its sweetness is somewhere between the short and long day types. Adapted varieties include Early Harvest, Amber Express, Pronto S, San Joaquin, Cimmaron, New Mexico Grano, and Superstar.

Production challenges include water-related disease such as purple blotch, and also botrytis which can rot the bulb in rainy climates. An orange rust fungus and also caterpillars can cause seasonal problems. Erratic weather with too much nitrogen can also produce double centers, which are considered a lower grade and definitely cannot be processed into onion rings. Onion and western flower thrips scrape on the surface of leaves, leaving unsightly white dashes, and predispose them to fungal and bacterial diseases. Thrips are also vectors of Iris Yellow Spot Virus (IYSV), which recently arrived on Maui and is raising havoc on sweet onions there. Major losses are expected from this disease since it lives on many weeds, and is also found on potted ornamentals, which is probably how it arrived on Maui.

Onions are among the few edible members of the lily family along with garlic and chives. Many lily flowers can be eaten, including the common orange day lily. Onions don’t compete well with weeds so fields must be kept weed-free. Fertilize frequently with low-dose balanced fertilizer. Molokai can grow sweet onions, especially in the upper parts of Ho`olehua, and even in Maunaloa. For more information, you can download a pamphlet on Green and Bulb Onion at http://www.ctahr.hawaii.edu/oc/freepubs/pdf/HGV-16.pdf.

Conservation Help Offered to Farmers

Monday, March 14th, 2011

With the help of generous funds from the government, farmers can take advantage of benefits that pay for conservation.

There are several conservation programs offered by the U.S. Department of Agriculture (USDA) to Molokai farmers. To be eligible, farmers must earn $1,000 a year and be producing some kind of crop or livestock. The programs specialize in water erosion prevention, wind erosion, soil management, waterway protection, manure management and more.

Ho`olehua farmer Rick Tamanaha has been participating in the Environmental Quality Incentive Program (EQIP) since 2005 by using windbreaks.

just want you to use good practice. It will only enhance your property and you’ll get better cattle,” Decoite said.

Interested farmers can contact Wally Jennings at his Ho`olehua office, 567-6868 ext. 105 or email wally.jennings@hi.usda.gov.