Kiwifruit Kiwifruit, sometimes known as Chinese gooseberry, or simply kiwi, is thought to have been discovered in various regions of China and was considered a delicacy among royals. Seeds from China were introduced to New Zealand in the 1900s and were exported to the United States in the 1950s. Today, the most common variety is the Hayward, grown almost exclusively in California and originating from the first known plants exported from New Zealand. Kiwis are fuzzy, brown, and about the size of a chicken egg, containing bright green interior fruit and tiny black seeds. The fruit grows on a woody vine that can reach up to 30 feet tall. References: California Kiwifruit Commission, Purdue University. SEASONAL AVAILABILITY CALIFORNIA CHILE CHINA FRANCE GREECE ITALY NEW ZEALAND References: California Kiwifruit Commission, Chilean Fresh Fruit Association, Encyclopedia of New Zealand, Purdue University, University of California Extension.
TYPES, VARIETIES & CUTS KIWIFRUIT There are generally three types of kiwifruit: grocery store kiwifruit (Actinidia deliciosa), hardy kiwifruit (Actinidia arguta), and super-hardy kiwifruit (Actinidia kolomikta). Grocery store kiwifruit (or fuzzy kiwifruit ) is the largest, most edible and most available of the three types. Hardy kiwifruit are known as bowerberry and trees can grow up to 100 feet tall in the forests of Japan, China, Korea, and Siberia and can withstand colder temperatures. The fruit is smooth-skinned, sweeter, resembles a grape, and is grown in clusters. The super-hardy kiwi is also smooth-skinned with even smaller fruit and can handle temperatures up to -40 F during the winter. It is sometimes referred to as the arctic beauty kiwifruit. There are more than forty known varieties of kiwi, spanning the globe from California to New Zealand to Greece. New Zealand s Hayward is the standard grown all over the world. In areas where there are growing limits due to colder temperatures, the Saanicheton variety has been known to survive where the Hayward has not. Other well-known varieties include Elmwood, Dexter, Abbott, Tewi, Vincent, Matua, Tomuri, Chico, Allison, Bruno, Gracie, and Monty. References: California Kiwifruit Commission, California Rare Fruit Growers, Rodale Press. PESTS & DISEASE Common Diseases: Agrobacterium tumefaciens or crown gall is a disease of the vine that can be avoided by leaving the upper roots exposed. Roots can also be attacked by Phytophthora cactorum and P. cinnamomi, along with oak root fungus, which cause a brown to black root rot, killing the entire plant. Botrytis cinerea is a disease that affects both the flowers and the fruit, and has been seen within all growing areas. The biggest threat to kiwis during postharvest is gray mold rot, which enters the skin of the fruit through small cracks when stored at high humidity. Psa-V, or kiwifruit vine disease (more common in Europe), is a bacterial cancer that causes halo-shaped spots on the leaves, brown discoloration of the buds, and release of a red-colored gum on the plant. It is spread through windborne pollen, heavy rainfalls, humans, and animals and is most apparent during cooler temperatures and high humidity. Common Pests: Rootknot nematodes are parasitic worms that attack the roots of plants, causing knots to form on the roots. The leafroller caterpillar (the most common and damaging pest) will eat holes in the fruit causing scarring, especially where two or three fruits are touching each other. In summer or early fall, thrips can cause browning of the leaves. Greedy scale insects infest the leaves, bark, and fruit, killing the growing tips of the plant. Heavy infestations cause scaling on the fruit. The boxelder bug tends to feed on the buds and fruit, causing deformities and the fruit to drop early. References: New Zealand Ministry for Primary Industries, Purdue University, University of Arkansas, UC Davis Integrated Pest Management. CULTIVATION, STORAGE & PACKAGING Preharvest: Kiwifruit can grow wherever citrus, peaches, and almonds are plentiful, but its leaves are more sensitive to cold than orange or peach trees. Young kiwifruit vines are killed by drops in temperature below 29 F, while mature vines can withstand temperatures below 10 F. For good growth, the plant will need deep, fertile, moist, and well-drained soil. Flowers of the plant are almost exclusively pollinated by insects.
CULTIVATION, STORAGE & PACKAGING CONTINUED KIWIFRUIT Postharvest: Kiwifruit is harvested by hand in a single pick once the fruit has reached maturity. They are packed in single-layer flats, with some fruit being placed in small consumer bags. Kiwifruit should be stored at 32 F with 90 to 95% relative humidity. Freezing injury can occur in colder temperatures and the fruit is extremely susceptible to the effects of ethylene gas. Use of controlled-atmosphere storage facilities is helpful for long-term storage to avoid production of ethylene. The use of electric forklifts to transport the fruit is recommended to avoid ethylene production. References: Oregon State University, Purdue University, UC Davis Postharvest Technology website, USDA. GOOD ARRIVAL GUIDELINES Generally speaking, the percentage of defects shown on a timely government inspection certificate should not exceed the percentage of allowable defects, provided: (1) transportation conditions were normal; (2) the U.S. Department of Agriculture (USDA) or Canadian Food Inspection Agency (CFIA) inspection was timely; and (3) the entire lot was inspected. Note that the percentage of allowable defects increases based on the number of days in transit, with five days for coast-to-coast transport by motor carrier considered normal. There are no good arrival guidelines for this commodity specific to Canada; U.S. guidelines apply to shipments unless otherwise agreed by contract. References: DRC, PACA, USDA. U.S. Grade Days Since % of Defects Optimum Standards Shipment Allowed Transit Temp. ( F) 12-6-2 5 15-8-3 32 4 14-8-3 3 13-7-2 2 13-6-2 1 12-6-2 KIWIFRUIT: WEEKLY MOVEMENTS & PRICES, USA Source: Chart by Gallo Torrez Agricultural Price Trends (GTAPT), mgallo@markfinstrat.com, compiled from USDA data.
INSPECTOR S INSIGHTS KIWIFRUIT Bruising is scored as a defect, against the U.S. No.1 Grade, when it causes a slight discoloration and exceeds an area of 3/8-inch in diameter; or if the bruise causes an indentation or discoloration of the flesh deeper than 1/8 inch If the fruit is in storage, moisture may evaporate, leading to shriveling. Shriveling found on the shoulders, or at the stem end, is scored as a defect against the U.S. No.1 Grade when it exceeds an area of 10% of the surface. Shriveling is always scored against the tolerance for serious damage Kiwifruit is one of the few commodities with a maturity requirement for the U.S. No.1 Grade. Soluble solids taken from 15 randomly selected fruit must meet a minimum of 6.5%. Source: Tom Yawman, International Produce Training, www.ipt.us.com.