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Coffee Pests and Diseases: Signs to Check by Plant Part

By Edward MillerPublished 6 min readcoffee origins

Quick Answer

Coffee leaf rust affects leaves, coffee berry disease damages fruit, and borers attack fruit, twigs or stems. Start with the affected plant part, then look for a more specific sign: powder beneath a leaf, a berry entrance hole, a sunken lesion or a hole beneath a dying twig. Those details help distinguish problems that can all cause yellowing, leaf loss or poor growth.

A leafy coffee branch bearing red cherries in a growing area.
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This guide follows living coffee plants and their fruit. If you are checking a potted Arabica at home, use indoor coffee plant care for the moisture, drainage, feeding and light checks that belong alongside a search for pests.

Start with the Affected Plant Part

Photograph the whole plant and the affected part before concentrating on one mark. A damaged leaf on an otherwise leafy shrub tells a different story from a dying twig or several declining trees.

Coffee Reference TableScrollable table
Coffee Reference Table
Where to lookPattern worth recordingNext closer look
LeavesYellow patchesCheck the corresponding underside for yellow-orange powder
LeavesBrown spots with pale centersRecord the margins, any yellow halo and whether berries also have lesions
FruitSmall entrance holesPhotograph the tip of the berry and note which stages of fruit are affected
FruitExpanding, sunken dark patchesRecord fruit ripeness, premature drop and whether damage is on one plant or several
Twigs or stemsWilting beyond a particular pointLook beneath the twig for an entrance hole and along thicker stems for ridging
Shoots and leaf undersidesWhite waxy clusters, attached bumps or sticky surfacesLook for insects, ants and black sooty growth together

The borers below are insects. Rust, brown eyespot and coffee berry disease are fungal diseases. A visible pattern narrows the questions to ask; identifying the cause also needs the plant's growing setting and, where necessary, examination of a sample.

Compare Leaf Marks on Both Surfaces

Coffee Leaf Rust

Look for yellow spots above and yellow-orange powder beneath the same leaf. Coffee leaf rust is caused by Hemileia vastatrix. The Hawaiʻi Department of Agriculture's January 2021 advisory shows how patches can enlarge, merge and develop brown centers. Infected leaves may fall prematurely.

The powder is a mass of fungal spores. Water allows spores to germinate and infect leaves; wind, rain and contact can spread them. Photograph both surfaces without rubbing the powder or moving suspect plants to another growing area. Follow the local plant-health service's instructions before taking a sample.

A variety described as rust resistant can still develop symptoms under some conditions. Our rust-resistance article explains the difference between resistance, immunity and performance at a particular site.

Brown Eyespot and Cercospora Leaf Spot

Pale-centered spots with darker borders suggest a different pattern from rust's orange powder. Brown eyespot, also called Cercospora leaf spot, is caused by Cercospora coffeicola. The centers can be tan, gray or whitish, with brown to darker margins and sometimes a yellow halo.

The same fungus can affect fruit, where the disease is called berry blotch. University of Hawaiʻi CTAHR's 2008 reference shows leaf and berry examples on printed page 2. It also explains that other fungi can follow damaged fruit and confuse identification. Record both leaf and fruit symptoms rather than naming a disease from the color brown alone.

Separate Berry Holes from Berry Lesions

A borer entrance is a small opening; a disease lesion is an area of damaged tissue. Look closely at the fruit's surface and stage of development. The coffee-cherry anatomy guide shows how the fruit surrounds the seeds we call beans.

Coffee Berry Borer

The female coffee berry borer, Hypothenemus hampei, bores into the fruit and makes galleries in the seeds. Larvae feed there too. The Coffee Board of India describes a pinhole at the berry tip, sometimes with additional holes in heavily attacked fruit.

Egg, larva, pupa and adult stages occur within the seed. Development time changes with temperature, and old berries on the tree or ground can carry the insect between crops. CTAHR's berry-borer resource includes photographs of entrances and galleries. For the insect's unusual relationship with caffeine, see how its gut bacteria help it break caffeine down.

Coffee Berry Disease

Coffee berry disease, or CBD, can begin as sunken dark spots that enlarge across green fruit. Affected berries may blacken and fall early. Uganda's December 2021 advisory identifies the causal fungus as Colletotrichum kahawae and describes confirmed disease in Arabica in the Sebei subregion.

Sunken fruit lesions can also occur with Cercospora berry blotch and other damage. Anthracnose is not a reliable interchangeable label for every dark coffee berry. Photograph the fruit, nearby leaves and the pattern across the plant for a local crop adviser.

Trace Twig Dieback Toward the Stem

Follow a wilting twig back toward healthy growth and look beneath it for an entrance hole. Black coffee twig borer, Xylosandrus compactus, attacks twigs and young stems. India's Coffee Board calls this insect shot hole borer. The 2019 Ugandan clonal Robusta nursery manual, printed page 36, shows twig damage and identifies the beetle. Uganda's 2021 advisory describes yellowing followed by darkening and wilting beyond the entrance point.

White stem borer, Xylotrechus quadripes, attacks a different part of the plant. India's Coffee Board describes external ridges on infested Arabica stems, together with yellowing and wilting. The FAO's 2005 Lao Arabica manual explains that young larvae tunnel beneath the bark before entering the wood.

Record where the damage begins: one thin twig, a thick branch or the main stem. A wilting plant without a visible entrance still needs other checks, especially its root zone and water supply. Routine farm pruning and cutting out a confirmed pest attack are different decisions.

Look for Insects Behind Sticky Leaves and Black Soot

Black sooty growth can point you toward sap-feeding insects and their honeydew. Check leaf veins, young shoots, leaf axils and berry clusters for scale bumps or mealybugs. Mealybugs, including Planococcus species, form white waxy colonies. Sticky honeydew and attending ants are useful accompanying observations.

The FAO Lao manual describes sooty mould growing on honeydew associated with scale and other sucking insects. The black coating and the insects producing honeydew belong in the same inspection. For a household plant, the indoor-care pest checks also explain where to look for mites and webbing.

Record the Pattern Before Choosing Control

Take a small set of clear observations to a local horticultural or coffee-crop adviser. Include:

  1. Plant and place: Arabica, Robusta or unknown; a pot, nursery or field; and the location.
  2. Affected part: upper and lower leaf surfaces, fruit, twig, stem or roots.
  3. Pattern: one plant or several, older or newer growth, and where damage first appeared.
  4. Timing: when it started, recent weather or watering changes, and any fertilizer or spray already used.
  5. Photographs: a whole-plant view, a close view with a size reference, and the underside or opposite side where relevant.

That record supports integrated pest management: identify the problem, monitor it, choose measures suited to the crop and site, then check the response. A treatment decision needs the confirmed problem and current local guidance, including the exact product label if a pesticide is proposed. A spray calendar from another country or an older manual does not supply those details.

Sources and Photo References7