Cacao disorders - Plantwise · CACAO 9 BACK TO CONTENTS • Postharvest pest casing damage to cacao beans • Larvae are 1.5-15 mm in length • There are small brown-black spots

1CACAO

KNOWLEDGE FOR LIFE

CABI PEST AND DISEASE PHOTOGUIDE TO

Cacao disorders

2 CABI PEST AND DISEASE PHOTOGUIDE

Introduction

This photo booklet has been produced by the CABI-led Plantwise programme (www.plantwise.org) in collaboration with The International Permanent Working Group for Cocoa Pests and Diseases (INCOPED) and funded by Mondelēz International to aid extension officers and other plant health advisors in diagnosing the most common pests, diseases and abiotic problems of cacao around the world. The symptoms presented on a real plant sample can be compared with the photos in this guide to identify possible causes. The booklet is organized into two broad sections, one showing the common insect pests that attack the crop and the other showing the various symptoms of poor health. In the symptoms section, the images are arranged by plant part, with similar-looking symptoms displayed together. Some biotic and abiotic factors cause more than one type of symptom, so there may be multiple images in different parts of the photo booklet for a specific problem. The photos for a particular problem are cross-referenced to make it easy to find all the relevant photos.

Evaluation of photosheets during a course in Nicaragua (Yelitza Colmenarez, CABI)

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Contents

Sign or symptom Box

Insects 1 – 29

Leaf 30 – 50

Pod 51 – 84

Stem 85 – 109

Root 110 – 113

Whole Plant 114 – 127


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• Larvae pupate in pale yellow, oval cocoons (13-18 mm long and 6-9 mm wide) that can be seen in leaf litter

3

Cocoa Pod Borer Conopomorpha cramerella Asia, Oceania

Photo: CABI

INSECT 1 5652 54 55532

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• Adults (left) are approx. 1cm long, roughly oval, with small protuberances on the body

• Antennae (A) are long and thin • Eyes are prominent (E)• Pronotum (P) is broader than long • Legs (L) are long and thin • Adults can fl y 1-2 km, this is the main mechanism of dispersal

4 595 58

Cocoa Mirid Sahlbergella singularis Africa

Photo: R Babin, CIRAD

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• Adult is a small (7mm) brown moth with yellow patches at the tip of the forewings

• Antennae are very long and swept backwards in their resting position

• Active at night

15652 54 553 532


Photo: CABI

INSECT

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• First-instar larvae are translucent white (1mm long)• Late-instar larvae are cream (10mm long)• Feeding causes damage and sticking together of the beans

21


Photo: CABI

INSECT 5652 54 55533

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• There are 5 nymphal stages• Nymphs are rounder and more reddish in colour than the adult

54

Cocoa Mirid Sahlbergella singularis Africa


INSECT 5958

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98

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• Adults (right) are approx. 1cm long, roughly oval, with small protuberances on the body

• Eyes (E) are small • Antennae (A) are short • Pronotum (P) is as broad as long • Legs (L) are short and thick• Adults can fl y 1-2 km, which is the main dispersal mechanism

67

Cocoa Mirid Distantiella theobroma Africa


INSECT 5958

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• There are 5 nymphal stages (plus adult on the right)• Nymphs are rounder and more reddish in colour than the adult

76

Cocoa Mirid Distantiella theobroma Africa


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• Adults are active during the day• Reddish brown or orange

8

Cocoa Mirid Monalonion spp. Central, America, S America

Photo: D Gopaulchan, CRC

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• Helopeltis antonii and feeding lesions on a cocoa pod• Adults are dark red or green to brown-black• Active during the day

910060 9910

Cocoa Mosquito Bug Helopeltis antonii Africa, Asia, Oceania

Photo: E Sulistyowati, ICCRI

INSECT

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• Five nymphal instars • Pear-shaped with yellow-orange to brown

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Cocoa Mosquito Bug Helopeltis antonii Africa, Asia, Oceania


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• Morphology of four common types of foliar feeding mealybugs on cacao

• Top left Ferrisia virgata• Top right Planococcus lilacinus• Bottom left Planococcus citri• Bottom right Planococcus kenyae

111312 791514

Various Mealybugs Worldwide

Photo: Anon.

INSECT

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• Females are wingless, oval and fl attened• Approx. 1-3 mm in length• The body is segmented, yellow in colour and coated with

white wax• P. citri has a characteristic faint grey stripe down their backs • Short waxy fi laments can be seen around the edges of the body

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Citrus Mealybug Planococcus citri Worldwide

Photo: C Olsen, USDA APHIS PPQ, Bugwood.org

INSECT

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• Small, segmented, slow moving insects with a dusty white-lilac (purple) coating

• Wider body shape and more rounded than other similarmealybugs

13

Cocoa Mealybug Planococcus lilacinus Worldwide

Photo: P Ooi, CABI

INSECT 7911

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• Small, segmented, slow moving dusty white insects visible on leaves, young shoots and berries

• Live in colonies usually on young tissue• Unlike other mealybugs adult female has a pair of dark

longitudinal stripes, long glassy wax threads, a ‘tail’ • Narrower body shape than other similar mealybugs

14

Striped Mealybug Ferrisia virgata Worldwide

Photo: G Goergen/IITA Insect Museum

INSECT 7911

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• This mealybug has a more prominent central line down the back of the adult compared to other similar mealybugs

• They have less wax than the citrus mealybug and the colour of the underlying insect is easier to see

15

Kenyan Mealybug Planococcus kenyae Africa

Photo: R Reeder, CABI

INSECT 7911

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• P. longispinus appear as white, waxy masses of mealybugs on stems, fruits and along the veins on the underside of leaves

• Two long, waxy fi laments protruding from the last abdominal segment of adult females

16

Long-tailed Mealybug Pseudococcus longispinus Worldwide

Photo: JW Lotz/Florida Department of Agriculture and Consumer Services/Bugwood.org

INSECT 79

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11


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• Adult females are soft bodied and wingless• Broad and oval in shape and shows distinct segmentation• Body colour beneath the wax covering is generally pink but can vary

from light chocolate or reddish brown to light yellow• Majority of P. njalensis can be found in the canopy 3–4 metres above

ground level• They occur in crevices on leaves, shoots, bark and pods• An important mealybug vector of cocoa swollen shoot virus (CSSV) in West Africa

17

West African cocoa mealybug Planococcoides njalensis Africa

Photo: F Oro, Université Péléforo-Gbon-Coulibaly

INSECT 79

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11

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• Young stinkbug nymph • Yellow to green in colour

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Stinkbug Bathycoelia thalassina Africa

Photo: B Oppong-Mensah, CABI

INSECT

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• Adult stinkbugs have long feeding stylets (2.2 cm) that can penetrate the pod cortex and cause feeding lesions

19


Photo: R Bateman, www.dropdata.org

INSECT 8218

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• Postharvest pest casing damage to cacao beans• Adults have grey-brown wings with vague darker markings• The wingspan is 11-20 mm

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Tropical Warehouse Moth Ephestia cautella Worldwide

Photo: CSIRO, Wikimedia Commons

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• Postharvest pest casing damage to cacao beans• Larvae are 1.5-15 mm in length• There are small brown-black spots down the body at the

base of each hair

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Tropical Warehouse Moth Ephestia cautella Worldwide

Photo: CSIRO, Wikimedia Commons

INSECT

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• Postharvest pest casing damage to cacao beans• Cacao beans may be hollowed out or tunnelled by the larvae• Adult is mottled dark-brown (3-5 mm long) • Adults bore circular holes when they emerge from the beans• Adult feeding causes irregular ragged patterns of damage,

particularly if previously damaged by larvae

22

Cocoa Weevil Araecerus fasciculatus Worldwide

Photo: G Goergen/IITA Benin

INSECT

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• Female ambrosia beetles 2.0-2.7 mm, Males 1.7-2.0 mm • Vector of Ceratocystis Wilt• Spores of C. cacaofunesta may be carried upon the bodies

of the beetles and can survive passing through the gut• Beetles are attracted to diseased plants and produce large

amounts of fi ne wood shavings (frass) when making breeding galleries in the trunk and branches

23115101

Ambrosia Beetles Xyleborus spp. Caribbean, Central America, S America

Photo: GJ Lenhard, Louisiana State University, Bugwood.org

INSECT

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• Small, soil-inhabiting, social insects• Similar in size and general appearance to ants• They have white (translucent) bodies with a white to

reddish brown head

2496

Termites Worldwide

Photo: S Bauer, USDA Agricultural Research Service, Bugwood.org

INSECT

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• Female moth has a red and black body with a brown head and dark wings

• larva exiting bore hole (inset)

25

Stem Borer Eulophonotus myrmeleon Africa

Photos: KF N’Guessan et al. (2014)

INSECT

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• Adult moth has a wingspan 30-50 mm• Thorax colour is white with four blue-black spots • The wings and abdomen also have dark spots

2627

Stem Borer Zeuzera coffeae Asia

Photo: Dr A Yakovlev, Flickr.com

INSECT

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• Larvae can grow to 50 mm• Orange to red in colour• Younger larvae are darker in colour • Larvae bore into branches and the trunk

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Stem Borer Zeuzera spp. Asia


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• Adult female is 10 mm long• Easily recognisable from the blue colour with black spots

and long antenna

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Shoot Borer Glenea celia Asia

Photo: B Sale, Wikimedia.org

INSECT

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11CACAO

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• Larvae bore into shoots and branches• Larvae have an enlarged fl at section behind the head which

makes them easily recognisable

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Shoot Borer Glenea spp. Asia, Oceania


INSECT

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• Most characteristic early symptom is yellowing (chlorosis) of a single leaf

• Chlorosis is not complete but contains scattered patches of green approximately 2–5 mm in diameter “green islands”

• The leaf is usually on the 2nd or 3rd fl ush behind the tip• Once the leaf falls symptoms develop in adjacent leaves

3012331 94 9532

Vascular Streak Die-Back (VSD) Ceratobasidium theobromae Asia, Oceania

Photo: A Daymond, University of Reading

FUNGUS

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• In Indonesia other symptoms have been seen where leaf necrosis (death) develops on green leaves

• These infected leaves remain attached to the branch for several weeks

31


Photo: P Keane

FUNGUS 12330 94 9532

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• White fungal growth and spores produced on cracks in the leaf veins and petioles (leaf stalks)

• Sporulation tends to occur during wet weather

32


Photo: P Keane

FUNGUS 12330 94 9531

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• Vein clearing/yellow banding in mature leaves, producing a ‘fernlike’ pattern on some cacao varieties

• Vectored by mealybugs

331161711 35 923416

Cacao Swollen Shoot Virus Disease (CSSVD) Badnavirus Africa, Sri Lanka

Photo: O Domfeh, CRIG

VIRUS

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• Yellowing (chlorosis) or fl ecking/mottling of mature leaves• Swelling of the stem nodes can also be seen • Vectored by mealybugs

34


Photo: A Whetten, UWE

VIRUS

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• CSSV causing red vein banding in young ‘fl ush’ leaves• The red colour can disappear as the leaf matures• Vectored by mealybugs

35


Photo: Dzahini-Obiatey, CRIG, Ghana

VIRUS

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• Dry, brown spots with yellow edges • Spots spread from the edge to the centre of the leaves• Eventually the leaves are completely damaged and fall off,

leaving the branches bare

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Anthracnose Colletotrichum gloeosporioides Worldwide

Photo: W Phillips Mora, CATIE

FUNGUS

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13CACAO

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• Young leaves are pale and reduced in size (a)• Leaves become thick and brittle with curling and/or

spiral twisting (b)

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Boron Defi ciency Worldwide

Photo: Illustration C Watts in Evans and Murray (1952)

DEFICIENCY

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• Young leaves show small white spots• Tip and margins become necrotic and die-back spreads from the

growing point (a)• Necrotic areas spread between the veins from the edge of t

he leaf. Necrotic areas merge into continuous marginal necrosis of older leaves (b)

• The unaffected area shows an oak-leaved pattern (b)

38

Calcium Defi ciency Worldwide


DEFICIENCY

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• Young fl ush leaves are a normal shape but smaller in size• Young shoots frequently look wilted• Tissue at the tip collapses and remains green for some

time (a, b)• Collapsed tissues later turns brown and forms a

wedge shape from the apex towards the midrib (c)

39

Copper Defi ciency Worldwide


DEFICIENCY

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• Younger leaves have dark green veins on pale green leaf tissue (a), or green veins with pale yellow/white leaf tissue (b)

• Drying of the tip (b)• Symptoms less prominent in leaves of the previous fl ush• Older leaves often show drying around the edge (b)

40

Iron Defi ciency Worldwide


DEFICIENCY

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• Necrotic areas occur between the veins near the leaf margin (a)• Areas of necrosis combine into a continuous marginal

necrosis on older leaves (b)• A bright yellow zone occurs at the front of the necrotic area

and islands of necrotic tissue often appear in advance of main necrotic margin (b)

• Unaffected areas are paler green and form an oak-leaved pattern (b)

41

Magnesium Defi ciency Worldwide


DEFICIENCY

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• Young leaves are pale yellow or yellow/green and develop a chlorotic pattern around the midrib (a)

• The main veins are dark green against pale background and necrosis occurs at the tip and margins (b)

42

Manganese Defi ciency Worldwide


DEFICIENCY

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• Young leaves are thin and translucent (a)• Developing mild chlorotic mottling (a, b)• Later developing scorch/necrosis around the leaf margin (c)

43

Molybdenum Defi ciency Worldwide


DEFICIENCY

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• Leaves pale/yellowish in colour and reduced in size (a)• Younger leaves have little or no green associated with the veins

and petioles have an acute angle with stem• Older leaves at the base may show tip scorch (b, c)

44

Nitrogen Defi ciency Worldwide


DEFICIENCY

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15CACAO

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• Plants can be stunted • Young leaves smaller in size, often with pale green colouration

between the veins• Mature leaves are pale towards tip and margin, scorch of the tip

margin follows

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Phosphorus Defi ciency Worldwide


DEFICIENCY

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• Pale yellow areas formed between the veins near the leaf margin (a)• Leaves quickly becoming necrotic (a) with necrotic areas

joining together around the margin (b)• Yellow zone on the inner edge of the necrotic zone

46

Potassium Defi ciency Worldwide


DEFICIENCY

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• Leaves of whole plant are pale yellowish or yellow/green but with no reduction in size

• Leaves bright yellow at fi rst with no green associated with the veins, later becoming pale yellow/green

47

Sulphur Defi ciency Worldwide


DEFICIENCY

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• Very young leaves have dark veinlets and are distorted in shape (a, b)• Leaves are narrow in proportion to length and margins are often

wavy (a, b, c) • Small chlorotic patches can occur between the veins (b)• Larger leaves show chlorotic patches in rows either side

of midrib and/or on the main lateral veins (d)

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Zinc Defi ciency Worldwide


DEFICIENCY

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• Younger leaves yellow and are cupped downwards with green veins (a) later developing necrotic tips and margins

• Older leaves have necrotic margins and necrotic areas where wounds occur (b)

49

Boron Toxicity Worldwide


TOXICITY

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• Pale yellow areas develop between the veins around the margin (a) quickly merging to form a necrotic area

• Tissues in advance of necrotic areas are various shades of dark green and grey (b)

50

Chloride Toxicity Worldwide


TOXICITY

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• Abnormally shaped pod (right) from an infected tree compared to a pod from a healthy tree (left)


51


Photo: K Kouakou, CNRA

VIRUS 11 35 9233

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• Beans are seen clumped together and are diffi cult to remove from the pods after harvest

• Beans may be discoloured (black), smaller, lighter in weight and have a fl at shape

52563 54 552 531


Photo: M Rutherford, CABI

INSECT

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17CACAO

• Larva of cocoa pod borer under silk membrane can be seen attached to pods (often in pod ridges)

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INSECT 563 54 552 521

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• Pods ripen prematurely and unevenly

54


Photo: CABI

INSECT 563 53 552 521

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• Larval entry (A) and exit holes (B) on pod

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INSECT 3 5421

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5352 56

• Internal pod damage by larva

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INSECT 553 53 542 521

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• Pod husk borer larvae feed on the husk of the pod • Damage to the pod allow entry of secondary fungal infection• Heavy infestation can cause severe damage to the pod and

losses in bean yields

57

Cocoa Husk Borer Various Worldwide

Photo: E Cartier-Bresson

INSECT

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• Feeding lesions on the pods appear as round black spots usually around the peduncle

• When the pod lies against the stem mirids hide in the sheltered area and the feeding lesions are grouped on the area closest to the stem

5875 64

Cocoa Mirids Sahlbergella singularis and Distantiella theobroma Africa

Photo: CRIG

INSECT

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• Heavy infestations and feeding can cause malformation of pods

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• Typical damage of Helopeltis spp. on mature pods• Feeding lesions are small black spots scattered over the

whole pod surface

60999 10

Cocoa Mosquito Bug Helopeltis spp. Africa, Asia, Oceania


INSECT

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19CACAO

• A young pod showing deformations (bumpy swellings) on the surface

• This is an early symptom to recognise the disease

6170666362 68 6965 6764

Frosty Pod Rot Moniliophthora roreri Central America, S America, Jamaica

Photo: J Crozier, CABI

FUNGUS

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• Young pod showing necrosis of the inner surface of the pod and infection spreading to the beans

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Photo: H Morales, CABI

FUNGUS 70666361 68 6965 6764

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• Young pod with swellings and irregular brown necrotic lesions on the surface

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FUNGUS 70666261 68 6965 6764

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• Premature ripening can be an indication of infection

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FUNGUS 70666261 68 6965 6763

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• An indication of infection is the appearance of brown “oily” on the pod surface

• Premature ripening of the pod around the “oily” spot

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FUNGUS 70666261 68 6964 6763

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• Irregular brown necrotic lesion appearing on pod• These lesions spread rapidly across the pod• This symptom is similar to those produced by Witches’ Broom

and Black Pod

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FUNGUS 70656261 68 6964 6763

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• White fungal mycelium develops within the brown lesion on the pod surface

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FUNGUS 70656261 68 6964 6663

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• Later stage of the disease on more mature pods• A thick layer of powdery cream/light brown coloured spores is

produced on the mycelial mat as it develops on the necrotic area • This is the most distinctive symptom to recognise the disease

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FUNGUS 70656261 67 6964 6663

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21CACAO

• Internal rot of the pod• Extensive internal breakdown of the pod and destruction

of the beans• Beans become a soft, watery mass attached to the pod wall• Similar to symptoms caused by Witches’ Broom

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FUNGUS 70656261 67 6864 6663

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• Pods gradually shrink and dry becoming hard and mummifi ed• The hard cream/brown covering on the pod is the remains

of the fungus • Infected mummifi ed pods stay attached to the tree

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FUNGUS 69656261 67 6864 6663

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• Irregular brown necrotic lesion on the pod• These lesions spread rapidly across the pod• This symptom is similar to those produced by Frosty Pod Rot

and Black Pod

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Witches’ Broom Moniliophthora perniciosa Caribbean, S America, Panama


FUNGUS

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• Internal pod damage, watery rot of beans and internal pod tissue• Beans become a soft, watery mass attached to the pod wall• Similar to symptoms caused by Frosty Pod Rot

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• “Strawberry” shaped pods also known as chirimoyas are often produced on infected cushions

• These deformed pods contain no beans

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• Brown lesion on pod surface• Brown lesions usually appear on the top or bottom of the pod• They expand rapidly over the pod in a week or two • A sparse covering of white spores appear on the brown lesion• A “fi shy” odour can be detected• Can be diffi cult to distinguish between different Phytophthora species

749376 7775

Black Pod Disease Phytophthora megakarya Africa

Photo: CABI

WATER MOULD

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• Brown lesion on pod surface• Brown lesions usually appear on the top or bottom of the pod• They expand rapidly and sometimes a sparse covering of white

spores appear on the brown lesion• A “fi shy” odour can be detected• Can be diffi cult to distinguish between different Phytophthora species

75

Black Pod Disease Phytophthora palmivora Worldwide

Photo: S Thomas, CABI

WATER MOULD 9376 7774

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• Mummifi ed pod in the late stages of Phytophthora spp. infection• The lesion covers the pod and is covered in spores• The pod dries but remains attached to the tree

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Black Pod Disease Phytophthora spp. Worldwide

Photo: S Thomas, CABI


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23CACAO

• The infection spreads from the outside of the pod into the internal tissues

• The beans eventually become infected and rot• Depending on the age of the pod when infected the beans

can remain healthy until harvest

77

Black Pod Disease Phytophthora spp. Worldwide

Photo: W Phillips-Mora, CATIE


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• Brown lesions and protrusions/swellings (warts) on the pod surface

• Damage occurs only to the pod and the beans remain healthy

78

Warty Pod Unknown Africa


UNKNOWN

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• Cacao pod with mealybug infestation• Mealybugs cluster between the ridges of the cacao pod

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Mealybugs Worldwide

Photo: E Hidalgo, CABI

INSECT

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• Infection appears as dark brown to black spots which spreads rapidly to cover the pod creating a “charcoal pod”

• Infection occurs on wounded or stressed pod• Cacao pod covered in sooty black fungal conidia

80

Lasiodiplodia Pod Rot Lasiodiplodia theobromae Africa


FUNGUS

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• Pods damaged by rats

81

Mammal Damage Rattus spp. Worldwide

Photo: PR Brown, ACIAR

MAMMAL

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• Pod deformation caused by Stinkbugs feeding on a young pod

821918



INSECT

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• Cacao pod showing dense white spore mass later becoming pinkish/brown

83

Mealy Pod Rot Trachyspaera fructigena Africa

Photo: AY Akrofi , CRIG

FUNGUS

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• Diseased pods develop brown lesions• White mycelia appear on the lesions, which turn pink when the

fungus produces spores• The diseased fruits eventually turn black

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FUNGUS

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25CACAO

• Terminal broom, with swollen stem

858973 87 887271 86


Photo: H Evans, CABI

FUNGUS

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• Infected fl ower cushion with fl ower showing swollen stems

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FUNGUS 8973 87 8872 85

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• Cushion broom growing from a fl ower cushion

87


Photo: T Peters, Ministry of Agriculture, Grenada

FUNGUS 8973 86 8872 85

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11771

• Dried brooms with small pink fruiting bodies• Close-up of a fruiting body (inset)

88


Photos: J Crozier, CABI (main), R Reeder, CABI (inset)

FUNGUS 8973 86 8772 85

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11771


• Proliferation of shoots on a branch producing a characteristic witches’ broom with many swollen stems growing from a single point

89



FUNGUS 8873 86 8772 85

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11771

• Strands of white thread fungus on cacao branch

90120

White Thread Blight Marasmiellus scandens Worldwide


FUNGUS

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• Strands of black thread fungus growing over a cacao branches and leaves

91

Horse Hair Blight Marasmius crinis-equi Africa, Asia, Caribbean, Oceania

Photo: CABI

FUNGUS 120

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• Characteristic swollen choupons growing from the stem of an infected plant


9211611 34 3533


Photo: E Muller, CIRAD

VIRUS

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1716 51

27CACAO

• The canker appears as a rusty-brown area on the bark of the stem, often with a sticky red gum (exudate) (top)

• When the bark is scraped away a reddish lesion can be seen on the tissue below (bottom)

937775 7674

Stem Canker Phytophthora spp. Worldwide

Photos: CABI (top), W Phillips-Mora, CATIE (bottom)

WATER MOULD

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• Rusty red staining seen inside the infected stem with comparison of healthy stem

• When a leaf is removed and the surface of the leaf scars (where leaves were joined to the stem) is scraped away with a fi ngernail, three black spots are visible (inset)

9412330 32 9531


Photos: CABI

FUNGUS

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• The most characteristic initial symptom is yellowing (chlorosis) of a single leaf, usually on the second or third fl ush behind the tip

• The Branch continues to grow normally beyond point of infection

95


Photo: P Keane

FUNGUS 12330 32 9431

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• Typical damage to cacao tree caused by termites• Termites can form colonies within the trunk or large branches

of the tree• Damage to the living wood can cause the death of the tree

9624

Termites Worldwide

Photo: J Vos, CABI

INSECT

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• Black elongated feeding lesions on a young shoot

9775 64



INSECT

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• A canker on the bark of a young branch caused by mirid feeding

98



INSECT 75 64

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• Small black elongated feeding lesions on a young shoot• Necrosis of the tissue causes drying of the shoot tip and dieback

9910010 609



INSECT

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• Feeding lesions develop into cankers (arrow) and can result in death of the bud

100



INSECT 9910 609

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29CACAO

• Characteristic discoloration of internal tissues of stem• Close up of the fungal fruiting bodies (perithecia) on

cacao xylem tissue (inset)• Can be vectored by ambrosia beetles (Xyleborus spp.) which

burrow into the cacao stem and spread the fungus

10111523

Ceratocystis Wilt Disease of Cacao Ceratocystis cacaofunesta Caribbean, Central America, S America

Photos: TC Harrington, Iowa State University (main) , C. Suárez-Capello, UTEQ (inset)

FUNGUS

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• Internal symptoms showing blackening of the infected vessels in the wood of the stem

102

Verticillium Wilt Verticillium dahliae Worldwide

Photo: E Boa, University of Aberdeen

FUNGUS 118

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• Borehole in the cacao trunk created by the larva

10325

Stem Borer Eulophonotus myrmeleon Africa


INSECT

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• Dieback of the infected branches with leaves turning brown• The branches are covered in pink to salmon coloured

(pale orange) fungal growth

104

Pink Disease Erythricium salmonicolor Worldwide


FUNGUS

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• Lobular gall has rounded appearance• No buds or fl owers

105

Lobular Gall Central America, S America

Photo: D Parra, Milagro State University

UNKNOWN

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• Hard woody smooth swelling approx. 2cm in diameter

106

Knob Gall Central America, S America

Photo: S Pérez-Martínez, Milagro State University

UNKNOWN

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• Stem-like growths develop in the shape of a fan

107

Fan Gall Central America, S America

Photo: R Rumbos, Milagro State University

UNKNOWN

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• Many closely packed fl owers are produced throughout the season

108

Flowery Gall Central America, S America

Photo: D Sosa, Milagro State University

UNKNOWN

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31CACAO

• Swollen fl ower cushions• Numerous tiny shoots are produced that do not develop into

normal fl owers• Buds remain green and unopened, giving the appearance of

“green points”

109

Green Point Gall Albonectria rigidiuscula Central America, S America

Photo: S Pérez-Martínez, Milagro State University

FUNGUS

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• Rosellinia pepo attacks cacao roots• White mycelial fans can be seen under the root bark

110

Black Root Rot Rosellinia pepo Worldwide

Photo: GM ten Hoopen, CIRAD

FUNGUS

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• Fruiting bodies of A. mellea at the base of the trunk is a sign of the later stages of the disease (a)

• White fungal mycelium can be seen growing under the dark (b)• If this is seen the tree will be heavily infected and will die

111

Armillaria Root Rot Armillaria mellea Worldwide

FUNGUS

Photo: JJ Guillaumin, CABI Plantwise (left), R Reeder, CABI (right)

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• Minor disease of cacao • White fungal mycelia have a string like appearance and age

to an orange-red colour• Fruiting bodies (large brackets fungi) can be seen after death

112

White Root Disease (on rubber tree) Rigidoporus lignosus Worldwide


FUNGUS

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• Cacao trunk showing brown encrustation at the collar/base of the tree

113119

Brown Root Disease Phellinus noxius Africa, Asia, Caribbean, Central America

Photo: B Ritchie, CABI

FUNGUS

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• Extensive feeding can cause the leaves to dry, turn brown and fall • Where this has occurred the trees are sometimes described

as ‘stag-headed’ trees

11475 64



INSECT

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• The leaves become limp and eventually dry and turn brown • These symptoms may be seen initially on only one side or

part of the tree• Eventually the entire tree will be affected and die, although

brown leaves may remain attached to the branches• Can be vectored by ambrosia beetles (Xyleborus spp.)

11510123

Ceratocystis Wilt Disease of Cacao Ceratocystis cacaofunesta Caribbean, Central America, S America

Photo: TC Harrington, Iowa State University

FUNGUS

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• Leaves gradually turn yellow and fall• The branches dry and turn brown from the tip (dieback) • The tree can eventually die

116


Photo: E Muller, CIRAD

VIRUS

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9211 34 35331716 51

33CACAO

• Terminal broom on a cacao seedling• The stem and side shoots are abnormally swollen

117898571 87 8873 8672



FUNGUS

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• Aerial symptoms showing chlorosis and drying of the leaves

118102

Verticillium Wilt Verticillium dahliae Worldwide

Photo: E Boa, University of Aberdeen

FUNGUS

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• Wilting and drying of the leaves caused by damage to the root system

119

Brown Root Disease Phellinus noxius Africa, Asia, Caribbean, Central America

Photo: Anon., CABI CPC

FUNGUS

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113

• Dead leaves held in position by the thread fungus

1209190

Thread Blight Marasmius scandens Worldwide


FUNGUS

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• The affected leaves dry and fall from the tree leaving only the bare branches

1218434



FUNGUS

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• Mistletoe with red/pink tubular fl owers

122

Mistletoe Tapinanthus sp. Worldwide

Photo: M. Schmidt, Wikimedia Commons

PARASITE

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• Necrotic leaves develop on infected trees

1239530 32 9431

Vascular Streak Die-Back (VSD) Ceratobasidium theobromae Asia

Photo: P Keane

FUNGUS

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• Rhizomatous fern with pinnately lobed leaves• Deeply sunken sori (structures producing the spores) on the

lower surface of the fronds that result in wart-like bumps on the upper surface

124

Monarch Fern, Wart Fern Phymatosorus scolopendria Africa

Photo: Aka Aka Romain, CNRA

EPIPHYTE

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35CACAO

• Leaves are leathery, bright green, 10 to 30 cm long and 2 to 4 cm wide

• Flower stalks are shorter than leaves are born at the base of the plant

• 5 to 10 white fl owers

125

Orchid Angraecum bracteosum Africa


EPIPHYTE

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• Large simple fronds with minute sori (structures producing the spores) that are scattered over the lower surface

126

Fishtail Fern Microsorium punctatum Africa


EPIPHYTE

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• Elongated hanging stems often up to 1m long with numerous aerial roots

• Numerous pendulous salmon-coloured fl owers with an unpleasant smell

127

Wax Orchid Diaphananthe bidens Africa


EPIPHYTE

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KNOWLEDGE FOR LIFE

AfricaGhana CABI, CSIR Campus No. 6 Agostino Neto Road Airport Residential Area P. O. Box CT 8630, Cantonments Accra, Ghana

T: +233 (0)302 797 202 E: [email protected]

Kenya CABI, Canary Bird, 673 Limuru Road, Muthaiga, PO Box 633-00621 Nairobi, Kenya

T: +254 (0)20 2271000/20 E: [email protected]

Zambia CABI, 5834 Mwange Close, Kalundu, P.O. Box 37589, Lusaka, Zambia

T: +26 (0) 967619665 E: [email protected]

AmericasBrazil CABI, UNESP-Fazenda Experimental Lageado, FEPAF (Escritorio da CABI) Rua Dr. Jose Barbosa de Barros 1780 Fazenda Experimental Lageado CEP:18.610-307 Botucatu, San Paulo, Brazil

T: +5514 38117670 E: [email protected]

Trinidad & Tobago CABI, Gordon Street, Curepe Trinidad and Tobago

T: +1 868 6457628 E: [email protected]

USA CABI, 745 Atlantic Avenue 8th Floor, Boston, MA 02111, USA

T: +1 (617) 682-9015 E: [email protected]

AsiaChina CABI, Beijing Representative Office Internal Post Box 85 Chinese Academy of Agricultural Sciences 12 Zhongguancun Nandajie Beijing 100081, China

T: +86 (0)10 82105692 E: [email protected]

India CABI, 2nd Floor, CG Block, NASC Complex, DP Shastri Marg Opp. Todapur Village, PUSA New Delhi – 110012, India


Malaysia CABI, PO Box 210, 43400 UPM Serdang Selangor, Malaysia


Pakistan CABI, Opposite 1-A, Data Gunj Baksh Road Satellite Town, PO Box 8 Rawalpindi, Pakistan

T: +92 (0)51 929 2064/2063 E: [email protected]

EuropeSwitzerland CABI, Rue des Grillons 1 CH-2800 Delémont, Switzerland


UK CABI, Nosworthy Way Wallingford, Oxfordshire OX10 8DE, UK


UK CABI, Bakeham Lane Egham, Surrey TW20 9TY, UK

T: +44 (0)1491 829080 E: [email protected] E: [email protected]

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Cacao disorders - Plantwise · CACAO 9 BACK TO CONTENTS • Postharvest pest casing damage to cacao beans • Larvae are 1.5-15 mm in length • There are small brown-black spots