Tuesday | August 22, 2017
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Coffee berry borer continues to impact growers

The beastie that is plaguing our coffee industry is not quitting. Coffee farmers continue to try to combat this voracious pest with limited success.

The coffee berry borer, Hypothenemus hampei, has been chomping coffee cherries all over the world for years. Native to Africa, the beetle has spread worldwide. After our drought in 2010, their numbers increased exponentially in the South Kona coffee district. Since they were first identified, the beetle population has expanded to most coffee farms in West Hawaii as well as coffee growing areas in Ka‘u. Though the Big Island is reeling from the attack, other Hawaiian islands have not, as yet, been affected. The damage the beetles are causing here has become a serious threat to our local coffee industry.

The best way to control this pest is for all coffee growers to participate in efforts to reduce their numbers. Leaving coffee trees untreated will not solve the problem and will probably make it worse. Participating by controlling the pest on your property is the best way to ensure the eventual reduction in damage.

The beetles bore into the flower end of a coffee cherry as it is developing and eat the actual beans as the cherries mature. Their destruction of the beans has caused losses of up to 80 percent of the crop among local coffee farmers. This is a serious problem that needs to be addressed by anyone growing coffee.

The first step is to assess the infestation of the borer on your property. It is easy to identify infested cherries on the trees. They have a small hole in the bottom of the bean and sometimes on the side. The hole looks like a needle has pierced the cherry. Just inside the skin of the cherry, the beetle is awaiting prime time to start eating the bean.

Check a few of your cherries that have the small hole. If the cherries are still green, you will likely find the beetle just under the green skin. This is a good time to try to kill the critter and save your beans by spraying.

Taking other countries’ experience into consideration, the basic combative techniques encompass several different practices.

Sanitation is important. Pickers must not drop cherries while harvesting. Collecting coffee raisins (old, dry cherries) from the trees at the end of the harvesting season removes the “CBB hotels” that these spent cherries provide.

At the end of the spring flowering, it is important to begin applying the fungus Beauvaria bassiana, saturating all trees in an attempt to get the fungus to contact and kill as many berry borers as possible. This fungus is currently available in two formulas. The organic brand is Mycotrol and the other is Botanigard. Either must contact the beetle to be effective. It is recommended to spray every 60 days, preferably in humid weather, and use a silicone surfactant to help the product adhere and spread for best results.

Setting traps which contain a liquid attractant and are designed to encourage the beetle to enter and drown may also be an effective way to control the beetle’s population. It is best to set traps a short distance from your trees so as not to attract beetles to your crop. Instructions on making traps can be found at ctahr.hawaii.edu/site/CBBTrap.aspx.

Several recent meetings have reviewed and offered modifications to these techniques that seem to work. Discussions have also focused on possible new ways to address the problem. Information on these practices as well as new developments in these and other techniques are constantly being presented at local meetings and workshops.

Two upcoming meetings promise more information. The Kona Pacific Farmers’ Cooperative will host a meeting Saturday, reviewing the basic information and offering some new developments. Three local experts will present information: Derek Shigematsu for the Hawaii Department of Agriculture, Andrea Kawabata from the UH Cooperative Extension Service and Alvin Sato from the local product supplier BEI will offer their perspectives on possible coffee berry borer control techniques. Details on this event can be found in the “Garden Events” section of this column.

On Aug. 24 and 25, the Kona Coffee Farmers Association is co-sponsoring a workshop at Kona Hongwanji featuring a presentation by Luis Aristizabal. He is an integrated pest management expert with years of experience dealing with the beetle in South and Central America. More information on this workshop and other updates are available at konacoffeefarmers.org.

Tropical gardening helpline

Judy asks: My turquoise jade vine recently produced an elongated green orb. Is this a seed pod? If so, can I use it to propagate more jade vine plants?

Tropical gardener advice: Though jade vines here do not often produce seed pods, it sounds like yours has. The green orb is probably three to four inches long and is hanging where an inflorescence was formerly hanging.

Yes, you can use the seeds to grow more plants. Many of us have found it very difficult to propagate jade vines from cuttings, so having seeds is very lucky.

You definitely don’t want to rush to harvest the seed pod. You want to wait until it starts to dry out and turn more brown than green. Once you notice it changing color you may want to put a net bag around the pod. You don’t want to cut off air circulation, but you do want to be sure to catch the seeds once the pod drops or breaks open.

Once the pod is dry, you can remove it from the vine and open it. Six to 10 seeds will probably be nestled inside. Prepare pots or a flat to germinate the seeds in by using a seeding mix that contains some vermiculite. A 50:50 mix of perlite and vermiculite work well.

Take the seeds and press them at least 1/4 inch into the damp seeding mix. Cover them and then cover the soil surface with a thin sheet of plastic to keep the soil warm and reduce evaporation. Place the container out of direct sun and check it periodically to be sure the medium has not dried out or become soggy. Germination should occur in two weeks or less.

When the seeds sprout, remove the plastic sheet and keep the soil moist. Once the seedlings have several true leaves, you can apply fertilizer and consider transplanting. Plant them where the vines can get support either from a trellis or a tree.

This is a great way to expand your jade vine plantings. You are fortunate to be able to propagate from seed. Good luck with them.

Garden events

c Thursday: “Hawaiian Ethnobotanical Art and Culture” begins at 2 p.m. at Tropical Edibles Nursery in Captain Cook with ethnobotanist Momi Subiono. Subiono will offer a presentation followed by an art reception. The art will be displayed in the gift shop for a month. The event is free and open to the public. For more information, call 328-9420 or email tropicaledibles@gmail.com.

c Saturday: “CBB Informational Meeting” from 8 a.m. to noon at Kona Pacific Farmers’ Cooperative at 82-5810 Napoopoo Road in Captain Cook. Three experts will speak on techniques to combat the coffee berry borer. For information or to register, call 328-2411.

c Farmer direct markets: The Hooulu Community Market is held Wednesdays from 10 a.m. to 3 p.m. at the Outrigger Keauhou Beach Resort’s Royal Gardens; Keauhou Farm Bureau Market, 8 a.m. to noon Saturdays at Keauhou Shopping Center; and South Kona Green Market, 9 a.m. to 2 p.m. Sundays above ChoiceMart in Captain Cook.

Plant advice lines are answered from 9 a.m. to 2 p.m. Thursdays at the South Kona cooperative extension service office, call 322-4892. Questions may be submitted anytime to master gardeners at konamg@ctahr.hawaii.edu or to the Kona Outdoor Circle at koc@konaoutdoorcircle.org.

Email plant questions to konamg@ctahr.hawaii.edu for answers by Certified Master Gardeners. Some questions will be chosen for inclusion in this column.

Diana Duff is a plant adviser, educator and consultant with an organic farm in Captain Cook.