Coffee stem borer prevention

Coffee stem borers bore underground tunnels in the stem, weakening the tree and causing it to die. Each lost tree can be equivalent to 4-5 years of productivity. Instructions for early detection and treatment of damaged plants for Central Highlands orchards.

Summary: The coffee stem borer *Xylotrechus quadripes* burrows underground in the stem. When you see the yellow and wilted tree, it is difficult to save. Unlike pepper stem borers (which can still be injected with rescue medication), coffee stem borers, once they destroy the main stem, often lose the tree. A orchard with 5-10 percent of trees infected with worms each year is a dangerous sign — the whole orchard needs to be treated.

Applies to: Robusta Coffee in Dak Lak, Lam Dong, Gia Lai, Dak Nong.
Duration: Room all year round, especially May-October.
Difficulty level: Medium.
Estimated additional costs: 2-4 million VND per hectare per year.

Characteristics of coffee stem borers

*Xylotrechus quadripes* is a beetle (hair clipping beetle), a species that specializes in coffee:

Adults are 13-20 millimeters long, dark brown in color with characteristic yellow stripes on the wings.
Lay eggs in cracks in the trunk, especially the main trunk below 1 meter.
Hatched larvae burrow inside, eat sap and wood tissue, creating tunnels 20-50 centimeters long.
Life cycle 8-14 months — slower than many other worms.
Strong breakout in May-October — adult worms are most active in laying eggs.

Detection signs

Holes on the body

2-5 millimeters round, larger than the hole in a pepper stem.
Coarse brown sawdust pushed out.
Common on the main stem, from the base up 1-2 meters.

Internal tunnel

When trying to cut the trunk (dead tree or being processed):

The chisel line is 20-50 centimeters long, 5-10 millimeters in diameter.
Sawdust and excrement deep in the tunnel.
The larvae can be seen to be 15-30 millimeters long, creamy white.

Tree symptoms

Yellow leaves wither, especially above the borer area.
The tree loses the ability to transport sap.
Can dry out in 6-12 months if worms destroy the main stem.

Seasonal Room

The beginning of the dry season (November-December)

Clean the orchard — cut off diseased branches.
Whitewash the base of the trunk to a height of 1-1.5 meters. Lime covers shell cracks — where adult worms lay eggs.
Check the stem for holes — mark the tree as having worms.

The beginning of the rainy season (April-May)

Spray *Chlorpyrifos* or *Cypermethrin* on body.
Spray evenly from the base up to 2 meters.
Repeat after 30-45 days.

Peak of rainy season (June-September)

Adult worms are the most active. Check monthly.
Additional spraying if the orchard has a history of epidemics.

Late rainy season (October-November)

Final spray to kill adult pests preparing to overwinter.

Treating decayed trees

The tree is in its early stages (1-3 holes, leaves are still green)

Step 1: inject treatment into the perforated hole.

Mix *Chlorpyrifos* concentration 0.3-0.5 percent.
Inject 1-2 milliliters into each hole using the syringe.
Clog the hole with clay or wax.

Step 2: spray the whole tree after 7 days.

Step 3: fertilize for recovery.

Heavy tree (many holes + yellow leaves)

The rescue rate is less than 30 percent. Consider:

Continue to treat if the tree has high value (large tree, orchard with few diseased trees).
Dig out and replace the tree with a new one if the damage is obvious — don't try to save it.

The orchard has many trees

When 5 percent or more of the plants have worms in the orchard:

Spray the entire orchard according to the regimen 2-3 times every 30 days.
Rotate *Chlorpyrifos* and *Cypermethrin*.
Improve hygiene — cut dry branches, remove peeling bark.

Periodic monitoring

[ ] Check the stems of 20-30 random plants each month.
[ ] Look for holes with new sawdust.
[ ] Assess the rate of worm-infected trees in the orchard.
[ ] Draw a map of the orchard recording the location of diseased plants.

Common mistakes

Skip checking the stem: only observe the leaves, don't see any small holes.

Low dose injection: does not kill larvae in the body.

Do not cover the hole after injection: the drug evaporates.

Spray on leaves instead of stems: adult worms lay eggs in stems.

High nitrogen fertilization: soft bark, easy for worms to lay eggs.

Take notes

orchard map — location of damaged plants.
Number of trees damaged each year.
Sprayed treatment + date.
Results of individual treatment of each tree.

References

*Prevention of stem borers in coffee* — Central Highlands Agricultural and Forestry Science and Technology Institute (abbreviated name WASI), 2022.
*Coffee pest management* — Plant Protection Department, 2023.