School Science Lessons
(ProjBan2)
2024-08-28
Banana Project, 2.
Contents
Preface
11.0 Pests and diseases
11.1 Bacterial soft rot of banana, Erwinia carotovora subsp. carotovora
Bacterial soft rots, DAF
11.2 Banana aphid, Pentalonia nigronerversa
See diagram 51.11.2: Banana aphid
Banana aphid, DAF
11.3 Banana bract mosaic disease, Banana bract mosaic virus, Kokkan disease, (BBrMV)
Banana bract mosaic virus, DPI
11.4 Banana bunchy top virus, (BBTV)
Banana bunchy top virus, (BBTV), Plant Health Australia
Bunchy top virus, DPI
11.5 Banana fruit-spot, Deightoniella torulosa, Banana Deightoniella leaf & fruit spot
Deightoniella torulosa (swamp spot, speckle, black tip is widely distributed disease, but nor a severe problem in well-maintained banana orchards.
It causes red-brown to black speckles on fruit skin and black fruit and can be controlled by good air circulation.
11.6 Banana leaf rust, Uredo musae
Banana leaf rust, Uredo musae, causes minute pustules on lower surface of older leaves, and small dark streaks which may form speckled blotches.
It occurs in Pacific Islands.
11.7 Banana leaf speckle, Metulocladosporiella musae
Banana leaf speckle, Leaf speckle, is widespread in tropics and sub-tropics, and in Central America, is frequently present with Ramichloridium speckle. Leaf spots are first visible as ellipsoid pale green flecks, forming pale to black-brown streaks up to 2 cm long, turning orange or dark brown, with age.
11.8 Banana mealybug, Pseudococcus elisae
Banana mealybug is most commonly found on banana, is well established in Central America and northern South America, and is similar to P. jackbeardsleyi.
It has waxy filaments around the body, about 2.5 mm long, female is covered with white wax over pale orange body.
In heavy infestations, the undersides of leaves become covered with the white ovisacs produced by the adult females.
Contamination of fruit for export may cause rejection at ports-of-entry where this mealybug does not occur.
11.9 Banana moth, Opogona sacchari, Sugarcane bud moth, Opogona glycyphaga
Sugarcane bud moth, DAF
11.10 Banana scab moth, Nacoleia octasema
Banana scab moth, DAF
Banana scab moth, Nacoleia octasema, (previously Lamprosema octasema)
The moth is small (25 mm wingspan), tan to light brown with small black spots on the wings.
The flattened eggs are laid in clusters ranging from a few to 30 eggs.
The eggs resemble shiny overlapping fish scales.
The yellow to orange larvae grow to about 25 mm before pupating.
Eggs are laid on or near to an emerging bunch and hatch after about four days.
The larvae feed on young female flowers and young fruit leaving a scab.
As the bracts and hands of bananas lift from the bunch stalk the larvae move to the next closed hand.
The life cycle egg to egg is completed in 28 days.
Adults live for only 4-5 days.
They hide in trash during the day and mate and lay eggs in the early evening.
The scars caused by the larval feeding form a black scab, so people do not like to buy or eat the fruit.
Control by clearing away any dead plant material around the plant base.
The scab moth has many natural enemies, e.g. spiders, so do not use chemicals that can kill these natural predator
11.11 Banana skipper butterfly, Erionota thrax
11.12 Banana spider mite, Tetranychus lambi
Banana spider mite, DAF
11.13 Banana spotting bug, Amblypelta lutescens, fruit-spotting bugs
Banana spotting bug, DAF
11.14 Banana streak disease, (CMV, Banana mosaic)
Banana streak disease causes yellow streaks from the midrib to the margin which later turn brown or black, similar to Cucumber mosaic virus symptoms
Infected plants become less vigorous, with smaller bunches.
It is spread by infected suckers planting material, untested plant tissue cultures and by mealybugs.
It is a minor problem in Lady Finger and Cavendish varieties, but causes rotting, split pseudostems, and plant death in Cavendish clones.
Control is by only using certified virus-free planting material, and by using white oils (cooking oil in water) or soap solution to control mealybugs.
11.15 Banana thrips, Chaetanaphothrips signipennis, Banana rust thrips
See diagram 51.11.15: Banana rust thrips.
Banana rust thrips, DAF
11.16 Banana thrips, Hercinothrips bicinctus, Banana-silvering thrips
Banana-silvering thrips, DAF
11.17 Banana weevil, Cosmopolites sordidus, Banana weevil borer
Banana weevil, Banana weevil borer, banana root borer, "banana beetle", Cosmopolites sordidus
See diagram 51.15: Banana weevil borer
Banana weevil borer, DAF
For control of Banana weevil borer:
1. Select clean land and keep land clean of weeds, dead leaves and trash.
2. Select clean suckers for planting material, because the weevils are spread to a new garden through infested suckers.
Clean the suckers by trimming them with a knife to remove the old roots where the weevils may hide.
Chop up the infested plants and feed them to your animals.
After harvesting the fruit, chop the stem into many small pieces and spread them around so that they dry quickly before weevils can lay eggs in them.
Keep the soil bare for 60 centimetres around the stool, so that the weevils do not lay their eggs in the banana plant.
Mulch your plants, but keep mulch and manure 60 centimetres from the banana plant, so they do not attract weevils.
3. Make weevil traps with cut pieces of corm placed cut side down on a small stone.
Weevils will live under the piece of corm.
These weevils can then be collected every few days and killed.
When replanting into old banana land, burn all banana residues and leave land left to fallow for at least six months after all residues have rotted down.
Ensure good plantation hygiene by removing all trash from the area around plants and suckers by raking all leaves into the inter row.
Cut up all fallen and harvested plant pseudostems to increase the rate of breakdown and destroy breeding sites.
Chemical control is possible if supervised by an officer of the Department of Primary Industry.
Brazilian farmers core out the centre of the banana stump once the bananas are harvested fill this deep core with water so that the females cannot lay their eggs there.
11.18 Banana wilt phytoplasma, Banana wilt associated phytoplasma, (BWAP)
See diagram 51.11.18: Banana wilt phytoplasma damage
Lethal yellowing diseases include Banana Wilt Associated Phytoplasma (BWAP) and the very closely related Bogia Coconut Syndrome (BCS).
BWAP and BCS infect banana, coconut, taro and betel nut plant in Papua New Guinea and in the Solomon Islands.
The phytoplasma is carried by insects, e.g. Lophops saccharicida and Zophiuma pupillata.
The leaves become yellow and die, the stem rots and the plant dies.
The best practice for the management of coconut lethal yellowing diseases is by immediate removal and destruction of infected palms.
Bacteria belonging to the genus Candidatus phytoplasma are responsible for disorders overseas in banana including banana wilt and banana elephantiasis disease.
Banana phytoplasma infection has been responsible for losses of up to 70 per cent in some banana crops in Columbia.
Several species of phytoplasma have been associated with banana wilting and other diseases overseas.
One species (Candidatus phytoplasma novoguineense) is present in Papua New Guinea, posing a nearby threat to Australia’s banana growing areas.
11.19 Sigatoka disease, Cercospora musae, Mycosphaerella musicola
Sigatoka disease, Cercospora leaf spot of bananas, (Cercospora musae), is the most damaging and economically important leaf disease threatening the cultivation of banana in developing countries.
. It occurs worldwide and by reducing the functional leaf surface of the plant, it causes in small, unevenly ripened bananas that fail to ripen and may fall.
It first appears as small, light yellow spots parallel to the side veins of leaves, which become larger in size and turn brown with light grey centres, until adjacent spots coalesce to form large, dead areas on the leaf.
Heart leaves of Gros Michel plants may have the typical leaf spot lesions of Cercospora musae, the perfect stage, called Mycosphaerella musicola.
Yellow Sigatoka (YS), leaf spot, Sigatoka leaf spot, Sigatoka disease of banana, Mycosphaerella musicola or Pseudocercospora musicola, reduces the plants' potential and bunch size, shorten the time between harvest and ripening (green life), which reduces fruit quality.
It usually occurs at the end of the wet season if bananas have not been sprayed with fungicides.
It can mask occurrence of the more destructive Black sigatoka, caused by Mycosphaerella fijiensis.
11.20 Black sigatoka of banana, Mycosphaerella fijiensis
Banana black Sigatoka, Mycosphaerella fijiensis (sexual state), Paracercospora fijiensis (asexual state), (previously Pseudocercospora fijiensis) Black sigatoka of banana, Black sigatoka disease, leaf spot, black leaf streak, caused by the ascomycete, Mycosphaerella fijiensis, occurs in most banana growing regions.
It causes the bananas to produce less fruit by destroying the leaves.
It starts as yellow steaks or 1 mm red brown flecks on the lower leaf surface that increase in size to form dark brown linear or elliptical streaks, 4-12 mm long, parallel to the leaf veins and visible on both leaf surfaces.
The streaks expand becoming elliptical spots often with a distinctive yellow halo.
As the lesions mature further, they become sunken and the centre turns grey.
In susceptible cultivars, high levels of disease can cause large areas of the leaf surface to die.
The disease can be spread by the movement of infected plant material, importation of infected germplasm, fungal spores produced on leaf lesions within dead leaf material on the plant, in trash and by spores dispersed by the wind or by water splash.
The unfurling and youngest fully expanded leaves on large plants and suckers are the most susceptible to infection.
As the leaves mature, they become resistant to infection.
Severely infected leaves can die, significantly reducing fruit yield, and causing mixed and premature ripening of bunches.
The disease spreads rapidly in hot, wet and windy weather if the banana project is not clean weeded and useless suckers not removed.
Badly infected leaves should be removed and burnt.
Control measures include the removal of older leaves to reduce inoculum levels, interplanting with other nonsusceptible crops, and planting in partial shade which results in less severe disease development.
Black Sigatoka has now replaced yellow Sigatoka to become the predominant leaf spot disease of banana.
Fungicide spraying and use of fogging with mineral oils will help to prevent this disease.
There is a tendency for resistance or tolerance to develop in M. fijiensis towards the systemic fungicides, so they are usually applied in combination or alternation with broad-spectrum, protectant fungicides, such as the dithiocarbamates and chlorothalonil.
Resistance to black Sigatoka among pre-existing banana genotypes is poor, Cavendish cultivars are very susceptible to it.
11.21 Brown flag syndrome in banana, Spodoptera litura, Cluster caterpillar
Cluster caterpillar, DAF
11.22 Burrowing nematode, Radopholus similis
Radopholus similis (burrowing nematode) is a major root pathogen, which causes lesions to roots and rhizomes, resulting in crop decline and tree toppling. Control with clean planting material soil treatment before planting, and use of nematicides if severe infestations.
It chews tunnels in the roots and corm and Fusarium oxysporum, infects the tunnels causing root rot.
The roots rot and weaken the plant that may topple over in strong wind after the heavy fruit bunches have formed.
Control by using land that has not grown bananas for at least three years and keep land clean of weeds trash.
Select clean suckers for planting material.
Treat planting material and infected soil with a nematicide, e.g. DBCP.
11.23 Cordana leaf spot, Cordana musae. Banana diamond leaf spot
Cordana leaf spot is a common disease, but it is a minor leaf spot disease on most banana varieties, but can be severe on plantain varieties.
The leaves have pale brown, oval patches on surrounded by bright yellow circles.
Control it with the same fungicides used to control the sigatoka diseases.
11.24 Crown rot and root rot, Rhizoctonia solani
Rhizoctonia solani, DAF
11.25 Freckle disease of banana, Phyllosticta cavendishii, Banana freckle P. musarum, P. maculata, Guignardia stevensii, (previously Phyllosticta musarum, Guignardia musae, (P. maculata, P. musarum)
Phyllosticta cavendishii, DPI
11.26 Fruit piercing moth, Eudocima materna
Fruit piercing moth, DAF
11.27 Fruit spot on banana, Corynespora torulosa
Fruit spot on banana, banana black tip; banana finger tip disease; banana leaf blotch; banana leaf spot; Deightoniella black tip of banana, occurs worldwide on different species.
It causes speckling of Cavendish banana fruits that leads to fruit quality deterioration and commercial rejection.
11.28 Hawaiian flower thrips, Thrips hawaiiensis, Banana flower thrips
Hawaiian flower thrips occurs in large colonies in flowers of many plants including banana.
It is a widespread species in tropical and temperate climates worldwide.
It punctures the leaves, flowers, or stems with its mouth parts and suck up the exuding sap.
The flowers become flecked, spotted, or deformed, depending on the extent of feeding.
11.29 Malayan leaf spot, Haplobasidium musae
Banana Malayan leaf spot occurs in the Pacific Islands.
Diamond shape, light grey, lesions with black borders appear on the upper leaf surface and fungus growth then spore release occurs on the under surface, and are spread in wind and rain.
It is a minor disease, and no control is needed.
11.30 Moko disease, Ralstonia solanacearum race 2, bugtok of banana, Blood disease
Blood disease, DPI
11.31 Oriental fruit fly, Bactrocera dorsalis
Bactrocera dorsalis is a highly invasive species found worldwide.
After introduction, it can easily disperse as it has a high reproductive potential, high biotic potential (short life cycle, up to 10 generations of offspring per year depending on temperature), a rapid dispersal ability and a broad host range.
It is highly competitive with native fruit flies where it has established, quickly becoming the dominant fruit fly pest. (CABI)
11.32 Panama disease of banana, Fusarium oxysporum forma specialis cubense, Fusarium oxysporum f.sp. cubense, Fusarium wilt of banana, Vascular wilt of banana
Panama disease, DAF
Panama disease (fusarium wilt), is caused by the soil fungus Fusarium oxysporum, which spreads by soil and water movement and infected planting material.
The first symptoms are yellowing and dying of the leaf edges, often mistaken for effects of water stress.
The leaves later collapse until the plant has the appearance of a stump with a skirt of dead or dying leaves and the water conducting tissue is discoloured.
The fungus enters through the roots especially if damaged by nematodes.
The plant cannot take up water, the leaves wilt, the cut stem has a fishy smell.
There is no sanitary control or chemical control available, but the "Cavendish" clones are highly resistant to this wilt.
Effects range from reduced yields to death of the plants.
The soil remains infested indefinitely so that only resistant varieties can be grown on that site in the future.
There is no treatment for Panama Disease, except to grow a resistant variety of banana, e.g. in the West Indies in the past they flood the infected land with sea water for several years.
When Lady Fingers are replanted, it takes a few years, but the disease eventually shows up again.
Goldfinger has some resistance to PD and is suitable for backyards.
11.33 Plague caterpillar, Tiracola plagiata, Banana fruit caterpillar
Banana fruit caterpillar, DAF
11.34 Queensland fruit fly, Bactrocera tryoni
Queensland fruit fly, DAF
11.35 Rhizome rot, Dickeya paradisiaca
Rhizome rot, fruit soft rot of banana, tipover, Phylum: Proteobacteria, Family: Enterobacteriaceae Dickeya paradisiaca
Use non-infected planting materials or tissue culture.
Select non-infected fields with good drainage.
Remove and destroy crop debris before cultivation and after harvesting.
Avoid damage to rhizomes by knives or cultivation tools.
This disease causes wilting and dying of newly-planted suckers, yellow of younger leaves, splitting at base of pseudostems, rotting of rhizome and central leaves, unpleasant rotting odour.
Pull out infected plants including all rhizomes and roots and destroy by deep burying or burning.
There is no chemical control for this disease.
11.36 Black cross disease of banana, Phyllachora musicola
Black cross, Phyllachora musicola, occurs in Australia, Indonesia, the Philippines, and Pacific Islands as is a minor leaf disease of banana. Black star-shaped lesions with points along the leaf vein axes on the undersides of older leaves
Control is not needed and Cavendish varieties are resistant to the infection
11.37 Soft rot on banana pseudostems, Pectobacterium carotovorum subsp. carotovorum
11.38 Tip rot of banana, Colletotrichum musae Banana tip rot, Anthracnose
Anthracnose, DAF
11.39 Two-spotted spider mite, Tetranychus urticae, Banana spider mite, Two-spotted mite
Two-spotted mite, DAF
11.40 Xanthomonas wilt and fusarium wilt
Comparing banana bacterial wilt caused by Xanthomonas campestris and fusarium wilt, caused by Fusarium oxysporum, by Richard Davis, Plant Pathologist
Bugtok (Tibagnol), is caused by a bacterium Pseudomonas solanacearum, carried by rasping, piercing and sucking insects.
Moko disease, is caused by Ralstonia solanacearum, a proteobacteria, is soil borne and causes bacterial wilt.
Blood disease is similar to Moko disease, the cause is not certain.
Panama disease is caused by the soil borne fungus, Fusarium oxysporum f. sp. cubense (FOC), which infects susceptible bananas through the roots causing a lethal vascular wilt.
1. Leaf symptoms
Blood disease and Moko disease: Leaves show a transient yellowing.
Wilt and die and hang down.
Eventually, a "skirt" of dead leaves remains around the pseudostem.
Xanthomonas wilt: Young leaves become yellow and die.
Compared to fusarium wilt: Wilt development is generally slower, so many leaves remain upright and rigid for much longer before they eventually die.
They become a characteristic bright yellow, which is easy to see from a distance.
2. Presence of a bunch
Blood disease, Moko, Bugtok: As infection through the floral raceme is common, a bunch of fruit is often seen in diseased plants.
Compared to fusarium wilt: Infections with most stains of Foc usually get too severe too early for a bunch to be produced.
3. Fruit symptoms
Blood disease: Fruit is outwardly unaffected, but internally is discoloured and may contain dry cavities or pockets of reddish brown mucoid tissue.
Moko: The fruit turn yellow and when cut show a firm brown rot that becomes grey.
Bugtok: Fruits of infected plants are internally discoloured red or brown and remain hard even when ripe.
Xanthomonas wilt: Fruit ripen unevenly and when cut, show a red brown internal rot.
Compared to fusarium wilt: If fruit are present there will be no discoloration inside green living fruits.
4. Internal vascular symptoms
Blood disease and moko: Internally brown vascular streaking can be seen throughout the plant, especially towards the centre of pseudostems and peduncles, and also in roots.
Cut vascular bundles exude bacterial ooze that is white to reddish brown colour (blood disease), or cream, yellow to brown to black (moko disease).
Bugtok: Vascular discoloration also occurs, but because the symptoms of bugtok are confined to the floral raceme, this does not usually extend far into the lower part of the fruit stem.
Xanthomonas wilt: Cut vascular bundles exude a yellow ooze.
Compared to fusarium wilt: Discoloration is readily seen in the pseudostem and would not occur in the fruit peduncles, if present.
Infected xylem vessels are seen as brown, red or yellow continuous vertical lines, which appear as rings in cross section.
Early in the process, before secondary rotting becomes extensive, there will be little or no discoloration in the centre of the pseudostem.
Later however, internal decay gets worse and brown secondary rotting, can be seen throughout.
5. Symptoms in suckers
Blood disease: Most suckers connected to the corm also become infected.
Compared to fusarium wilt: Suckers can often appear completely healthy and symptom less even though they are usually full of Foc microconidia.
Preface
Before teaching this project, discuss the content of the lessons with an agriculture extension officer and get advice on planting material, planting distances, a site for planting, approved mulch, composting, and control of pests and diseases.
Use only the procedures, agricultural chemicals and insecticides recommended by the local agriculture extension officer.
If you cannot control insects by hand-picking, ask the Ministry of Agriculture to recommend a chemical spray.
All insect sprays are dangerous.
Show the students how to use them safely.
Do not get the spray onto your hands.
Do not breathe in the spray.
Wash your hands well after using spray.
Keep the spray container in a safe place where students cannot get it.
Spray on a day of no wind, but if you must spray when there is a wind, spray down wind.
Make sure the spray does not blow on other people.