Coffee White Stem Borer
Not known to occur in Hawaii
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Xylotrechus quadripes or the Coffee White Stem Borer, is an insect pest not yet found in the Hawaiian islands.
General insect description: Larvae are pale yellow with a dark colored head. Adults are 2-2.5 cm long, slender, and black with distinct white markings. Plant damage: Larvae feed on wood internally, in the main stem and major branches. When mature, adults will leave exit holes 2-4 mm in diameter. Wood dust may be found on ground nearby entrance holes. Other signs of coffee white stem borer include wilting, defoliation, or yellowing of leaves. Tunneling larvae may also cause ridges to develop on the surface of the stem. |
Biology:
Female beetles deposit eggs in the cracks and crevices and under the loose scaly bark of the main stem and thick primaries, preferring the plants exposed to sun light. A female can lay about 100 eggs in groups of I to 10 during its life span of 9 to 30 days.
Eggs are small (1.3 mm in length and 0.5 mm in dial, whitish and hatch in 9 to 15 days. Hatched out grubs feed in the corky portion just under the bark for about two months. Later the larvae enter into the hardwood and make tunnels in all the directions. The tunnels are tightly filled with the excreta of the grubs. The total grub stage lasts about 10 months. The full grown grub is pale yellow and about 2 to 3 cm long. Pupation takes place in a chamber close to the periphery of the stem. The pupal stage lasts for 3 to 4 weeks, after which it transforms into an adult. The adult remains in the tunnel for 3 to 7 days, and emerges out by cutting an exit hole in the bark. The exit hole on the stem indicates that the borer has completed its life cycle and emerged as an adult. The total life cycle of the borer is completed in about a year.
Emergence season of adults of the borer is known as flight period. There are two peak flight periods i.e., one from April to May and the other from October to December. However, emergence of beetles in small numbers was recorded during other months also. Cloudy and wet weather conditions delay the emergence of the beetles by a week or two.
Arabica coffee is the most preferred and principal host plant.
Alternate host plants include robusta and tree coffee, teak, Olea dioica etc. However, the borer usually does not breed in these plants.
Female beetles deposit eggs in the cracks and crevices and under the loose scaly bark of the main stem and thick primaries, preferring the plants exposed to sun light. A female can lay about 100 eggs in groups of I to 10 during its life span of 9 to 30 days.
Eggs are small (1.3 mm in length and 0.5 mm in dial, whitish and hatch in 9 to 15 days. Hatched out grubs feed in the corky portion just under the bark for about two months. Later the larvae enter into the hardwood and make tunnels in all the directions. The tunnels are tightly filled with the excreta of the grubs. The total grub stage lasts about 10 months. The full grown grub is pale yellow and about 2 to 3 cm long. Pupation takes place in a chamber close to the periphery of the stem. The pupal stage lasts for 3 to 4 weeks, after which it transforms into an adult. The adult remains in the tunnel for 3 to 7 days, and emerges out by cutting an exit hole in the bark. The exit hole on the stem indicates that the borer has completed its life cycle and emerged as an adult. The total life cycle of the borer is completed in about a year.
Emergence season of adults of the borer is known as flight period. There are two peak flight periods i.e., one from April to May and the other from October to December. However, emergence of beetles in small numbers was recorded during other months also. Cloudy and wet weather conditions delay the emergence of the beetles by a week or two.
Arabica coffee is the most preferred and principal host plant.
Alternate host plants include robusta and tree coffee, teak, Olea dioica etc. However, the borer usually does not breed in these plants.
If suspected, what do I do?
- Contact and report your find immediately to the Hawaii Department of Agriculture by calling their toll-free pest hotline at 808-643-PEST (7378) or by contacting your nearest UH CTAHR Cooperative Extension office (also listed below). Listen carefully to their instructions. Their instructions may supersede any of the instructions below.
- Big Island - Kona - 808-322-4892; Hilo - 808-969-8201; Kamuela - 808-887-6183
- Maui - Kahului - 808-244-3242 x222
- Molokai - Hoolehua - 808-567-6929
- Oahu - Honolulu - 808-956-7290; Pearl City - 808-453-6050; Wahiawa - 808-622-4185
- Kauai - Lihue - 808-274-3471
- If possible, capture the insect (caterpillar or beetle) in a jar or container that prevents escape and if it can be done safely.
- Freeze the insect immediately. Do not smash or damage as identification will be difficult to impossible.
- Collect samples of damaged plant parts caused or thought to be caused by this pest.
- For leaves and branches - Refrigerate, but DO NOT FREEZE. Be sure that the pest (assume it is present) cannot escape the container or bag that the leaves are kept in. Double bag or containerize if necessary.
- Take clear photos and/or video of the insect and damage whether capture is possible or not, and provide them to HDOA and the Cooperative Extension agent.
- Flag or visibly mark the area where the pest was found and communicate the find with all farm employees and administrators .
- Keep people and pets away from the area and DO NOT allow movement of soil, plant materials or supplies from the location that the pest was found.
- Provide HDOA and the Cooperative Extension agent with information such as your name and contact, the exact location and address of find, and type of host material where found. Personal information will not be shared with the general public.
Prevention of new pest and disease introductions to Hawai
Comply with all HDOA and USDA quarantine regulations. Quarantine restrictions have been placed on unroasted coffee, coffee seeds, plants and other propagative materials, used coffee materials and supplies, etc.
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