Banana leaves turning yellow

Backyard Bananas

Jerry Coleby-Williams

JERRY COLEBY-WILLIAMS: I love my bananas. Some I cook and eat green as an alternative to potato, but most of them I enjoy sweet as a ripe fruit. This one behind me is Lady Finger. (Musa acuminata’Lady Finger’). It’s a really popular commercial variety because it has a thick skin and that enables it to travel safely to the supermarket. And this variety is Gold Finger (Musa acuminataxMusa balbisiana’Gold Finger’) – it’s another popular commercial variety, but like all bananas, they need regular care and attention to get the best results and that’s what I want to talk to you about today – starting with bagging.

I made my own banana bag and put those on the bananas right at the beginning. That stops flying foxes from scratching the fruit as they climb over the bunches to drink the nectar, but more importantly, when the fruit are fully formed, start cutting off hands and ripening those indoors. I wanted to show you a fully ripened bunch on this tree, so I left the bag on too long and the smell of the ripening fruit drove the flying foxes crazy. They ripped open the bag and look at the result! I’ve lost half of my fruit. So remember – ripen your bananas indoors.

This variety is Dwarf Ducasse (Musa acuminata’Dwarf Ducasse’) and it’s a compact form of banana – very tasty. It’s ideal for small gardens. Now have a look in here. When a stem has fruited it dies and you have to remove this close to the ground. By doing that, you remove the chance of banana weevils attacking the base of the plant. Now all around here is a thicket of suckers and they’ve all grown from the base of that plant. A strong, healthy banana just needs three suckers – all the rest can go and by removing them, I’m going to direct the energy into fruit production, not leaves.

Bananas really are high maintenance plants. Left to their own devices, they won’t thrive because for centuries, we’ve bred them for high quality, high volume fruit and along the way, the poor old banana has lost the ability to produce seed, so it can only reproduce vegetatively – either through suckers or more often these days, through tissue culture in the laboratory.

This is what we’re after – 3 suckers. The biggest one – this is what we call the leader and these 2 small ones – these are the followers.

Now fertilising. All bananas are veracious feeders – especially this one here ‘Bluggoe.’ It’s a really big fruiting banana. I give all my bananas 3 litres of poultry manure every six weeks – except during winter. I like to cover the manure with compost to stop it being washed away by heavy rain. If your bananas fail to flourish despite being well watered and pampered like this, you could well have a pest or disease problem.

Samantha Stringer is a banana council inspector. She travels throughout south-east Queensland and northern New South Wales checking that backyard bananas aren’t harbouring pests and diseases that could harm the industry.

SAMANTHA STRINGER: There’s two main diseases we have – one being Panama Disease which is a fungus that is soil-borne, so it’s really important not to move banana plants around, but also you can move Panama via soil on your shoes and tyres and things like that, so it’s not really something we can control but the other disease that we have is Bunchy top Disease and that can be controlled.

Bunchy top is a virus that’s spread by the banana aphid and what it does essentially is it stunts the growth of the plants and stops them from producing fruit. The new leaves get shorter and narrower and stand more upright. The definite symptoms of bunchy top – you can see on the underside of a leaf when you’re looking up to the sun. So the new leaves get these dark dot-dash lines through the leaves which hook into the midrib and you also get dark green stripes up the midrib as well.

JERRY COLEBY-WILLIAMS: What should a gardener do if they think they’ve got a diseased banana?

SAMANTHA STRINGER: The first thing is, don’t chop it down cause that can spread the virus onto other plants in the area. Give us a call on the Bunchy Top Hotline (1800 068 371) and we’ll come out and check your plants for you. If they are diseased, we can treat them for you as well.

JERRY COLEBY-WILLIAMS: Gardeners love to swap plants, but you wouldn’t swap bananas would you?

SAMANTHA STRINGER: No well when you move banana plants around, you can essentially move these two diseases so it’s really important that if you want to get some banana plants for your backyard to access them through an accredited nursery and you can ring your local authorities to find out how you can do this.

JERRY COLEBY-WILLIAMS: Bananas are well worth growing and if you do, be sure to give them lots of tender loving care and keep your eyes open for bunchy top.

Tree pests and diseases

There are many things you can do to prevent or minimise the introduction, establishment, spread and impacts of tree pests and diseases, including:

  • learning to recognise and report pests and diseases of concern
  • adopting good biosecurity practice to avoid the spread of organisms from place to place
  • not bringing soil or plants back from holidays abroad

Understand the threat to our trees

The damage to our trees, woods and forests from insect pests and organisms such as bacteria and fungi is significant. The rapid increase in movements of goods and people between countries has increased the risk of spreading pests and diseases. They can travel hidden in plants, plant products, packaging, wood, vehicles and holidaymakers’ luggage – even in the soil carried on shoes.

Some of these pests and diseases do little harm in their native environments, where predators, environmental factors and co-evolution with their host plants keep them in check. However, they can cause significant damage to trees and plants in other countries where those limiting factors are not present. Some single species of insect, fungus or bacterium can damage or kill dozens of different plant species, including trees. As well as causing economic losses for the forestry, timber and plant-based industries, they can disrupt other sectors, such as tourism, and threaten woodland biodiversity, ecosystems and native species.

Get notifications about tree pests and diseases

Sign up for, and read previous editions of, the Forestry Commission’s Tree Health News newsletter.

Follow the Forestry Commission on Twitter.

Contact the tree health teams

Make a general enquiry about tree, woodland and forest health in England

For the rest of the UK, see:

  • tree health in Wales

  • tree health in Scotland

  • tree health in Northern Ireland

You can also find more information on scientific research into tree pests and diseases.

Photographs showing bananas with unusual red discolorations inside have been passed around online with varying degrees of paranoia for several years:

I bought a bundle of bananas from the Walmart in Aberdeen tonight and opened it to give to my 2 yr old daughter. This is what I found on the inside! I opened the rest of the bundle and they appeared to be normal bananas. I’m not saying it’s blood but what else would it be?! One banana out of the whole bundle was like this … a little weird! Check your produce before eating it. You never know what someone put in there.

The claims associated with the photographs have evolved from speculation about the discoloration of the bananas (as seen above) to assertions that the discoloration was due to someone’s purposefully injecting bananas with “infected blood” in order to spread HIV:

This form of reddish discoloration in bananas has nothing to do with blood of any sort, however: It’s a hallmark of a fungal or bacterial diseases that affect bananas grown in some areas and can cause their centers to turn dark red. Although the discoloration may make bananas seem visually unappealing to consumers, the plant diseases that cause it pose no real health risk to humans who eat such bananas:

There are a variety of plant diseases that can cause the inside of bananas to take on a red discolouration. This discolouration has led to false claims of bananas containing blood.

Nigrospora is a fungal disease that causes the centre of the banana to turn dark red. Nigrospora can infect the fruit in tropical climates where bananas are grown.

Mokillo, moko, and blood disease bacterium are bacterial diseases that can also cause red discoloration in bananas.

While unappealing to eat, these diseases affecting bananas are not a threat to human health, however when in doubt, throw it out or compost them.

As we noted in another article about a rumor concerning supposed blood-tainted oranges, it is nearly impossible for the HIV virus to be transmitted via foodstuffs:

Except for rare cases in which children consumed food that was pre-chewed by an HIV-infected caregiver, HIV has not been spread through food. The virus does not live long outside the body. You cannot get it from consuming food handled by an HIV-infected person; even if the food contained small amounts of HIV-infected blood or semen, exposure to the air, heat from cooking, and stomach acid would destroy the virus.

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Info On Banana Plant Pests – Learn About Banana Plant Diseases

Bananas may be one of the most popular fruits sold in the United States. Grown commercially as a food source, bananas also feature prominently in warm region gardens and conservatories, making striking additions to the landscape. When planted in areas with plenty of sun, bananas are not all that hard to grow, but problems with banana plants are bound to crop up nonetheless. What kinds of banana plant pests and diseases are there? Keep reading to find out how to solve problems with banana plants.

Growing Banana Plant Problems

Bananas are monocotyledonous herbaceous plants, not trees, of which there are two species – Musa acuminata and Musa balbisiana, native to Southeast Asia. Most banana cultivars are hybrids of these two species. Bananas were most likely introduced to the New World by Southeast Asians around 200 B.C. and by Portuguese and Spanish explorers in the early 16th century.

The majority of bananas are not hardy and are susceptible to even a light freeze. Extreme cold damage results in the dieback of the crown. Leaves will also naturally shed in exposed areas, an adaptation to tropical storms. Leaves may droop from under or over watering while brown edges indicate a lack of water or humidity.

Another growing banana plant problem is the plant’s size and propensity to spread. Keep that in mind when locating a banana in your garden. Along with these concerns, there are many banana pests and diseases that may afflict a banana plant.

Banana Plant Pests

A number of insect pests can affect banana plants. Here are the most common:

  • Nematodes – Nematodes are a common banana plant pest. They cause rotting of the corms and act as a vector to the fungus Fusarium oxysporum. There are a number of different species of nematode that like bananas as much as we do. Commercial farmers apply nematicides, which when properly applied, will protect the crop. Otherwise, the soil has to be cleared, plowed and then exposed to the sun and left fallow for up to 3 years.
  • Weevils – The black weevil (Cosmopolites sordidus) or banana stalk borer, banana weevil borer or corm weevil, is the second most destructive pest. Black weevils attack the base of the pseudostem and tunnel upward whereupon a jelly-like sap oozes out from the entry point. Different pesticides are used commercially depending upon the country to control black weevils. Biological control utilizes a predator, Piaesius javanus, but has not been shown to have any truly beneficial results.
  • Thrips – Banana rust thrips (C. signipennis), as its name suggests, stains the peel, causing it to split and exposes the flesh which then begins to rot. Insecticidal dust (Diazinon) or a spraying of Dieldrin can control thrips, which pupate in the soil. Additional insecticides combined with polyethylene bagging are also used to control thrips on commercial farms.
  • Scarring beetle – The banana fruit scarring beetle, or coquito, invades the bunches when the fruit it young. The banana scab moth infests the inflorescence and is controlled with the use of an injection or dusting of pesticide.
  • Sap-sucking insects – Mealybugs, red spider mites and aphids may also pay a visit to banana plants.

Banana Plant Diseases

There are quite a number of banana plant diseases that can afflict this plant as well.

  • Sigatoka – Sigatoka, also known as leaf spot, is caused by the fungus Mycospharella musicola. It is most commonly found in areas of poorly draining soil and areas of heavy dew. The initial stages show small, pale spots on the leaves that gradually enlarge to about a half-inch (1.25 cm.) in size and become purple/black with gray centers. If the whole plant is infected, it looks as if it has been burned. Orchard grade mineral oil can be sprayed on the banana every 3 weeks for a total of 12 applications to control Sigatoka. Commercial growers also use aerial spraying and systemic fungicide application to control the disease. Some banana cultivars also show some resistance to Sigatoka.
  • Black leaf streak – M. fifiensis causes Black Sigatoka, or Black Leaf Streak, and is much more virulent than Sigatoka. The cultivars that have some resistance to Sigatoka show none to Black Sigatoka. Fungicides have been used to try and control this disease on commercial banana farms through aerial spraying but this is costly and difficult due to scattered plantations.
  • Banana wilt – Another fungus, Fusarium oxysporum, causes Panama disease or Banana Wilt (Fusarium wilt). It begins in the soil and travels to the root system, then enters the corm and passes into the pseudostem. Leaves begin to yellow, starting with the oldest leaves and moving in towards the center of the banana. This disease is lethal. It is transmitted through water, wind, moving soil and farm equipment. On banana plantations, fields are flooded to control the fungus or by planting a cover crop.
  • Moko disease – A bacterium, Pseudomona solanacearum, is the culprit resulting in Moko Disease. This disease is the chief disease of banana and plantain in the western hemisphere. It is transmitted via insects, machetes and other farm tools, plant detritus, soil, and root contact with ailing plants. The only sure defense is to plant resistant cultivars. Controlling infected bananas is time-consuming, expensive and resistant.
  • Black end and Cigar tip rot – Black end stems from another fungus that causes anthracnose on the plants and infects the stalk and fruiting end. Young fruit shrivels and mummifies. Stored bananas afflicted with this disease rot. Cigar tip rot starts in the flower, moves to the tips of the fruit and turns them black and fibrous.
  • Bunchy top – Bunchy top is transmitted via aphids. Its introduction almost wiped out the commercial banana industry in Queensland. Eradication and control measures along with a quarantine area have managed to stamp out the disease but growers are eternally vigilant for any signs of bunchy top. Leaves are narrow, short with upturned margins. They become stiff and brittle with short leaf stalks that give the plant a rosette look. Young leaves yellow and become wavy with dark green “dot and dash” lines on the undersides.

These are just some of the pests and diseases that can afflict a banana plant. Vigilant attention to any changes in your banana and prompt attention will keep it healthy and fruitful for years to come.

Pests and diseases of banana crops

Identifying pests and diseases early can help you to better control and manage them. Pests and diseases that affect the banana industry are listed below.

Pests

  • Banana aphid
  • Banana flower thrips
  • Banana fruit caterpillar
  • Banana rust thrips
  • Banana scab moth
  • Banana weevil borer
  • Banana-silvering thrips
  • Banana-spotting and fruit-spotting bugs
  • Cluster caterpillar
  • Fruit piercing moths
  • Queensland fruit fly
  • Spider mite
  • Two-spotted mite
  • Sugarcane bud moth

Diseases

  • Anthracnose
  • Rhizome soft rot
  • Banana leaf rust
  • Leaf speckle
  • Crown rot
  • Fruit speckle
  • Yellow Sigatoka
  • Burrowing nematode

Serious quarantine pests and diseases

These diseases are present in Australia and pose a significant threat to Queensland’s banana industry. To prevent the introduction and spread of these diseases, to and within Queensland’s banana production area, movement restrictions apply to banana plants, and banana pest carriers.

  • Banana freckle
  • Black Sigatoka
  • Bunchy top
  • Panama disease TR4

Serious exotic pests and diseases

These diseases are not present in Australia. They pose a significant threat to Queensland’s banana industry.

Also consider…

Pest & Disease Control for Banana Plants

Every plant has the future potential for disease and insect damage. Factors such as location and weather will play a part in which issues your plants encounters. If available, disease-resistant varieties are the best option for easy care; and for all types of plants, proper maintenance (such as watering, pruning, spraying, weeding, and cleanup) can help keep most insects and diseases at bay.

NOTE: This is part 7 in a series of 11 articles. For a complete background on how to grow banana plants, we recommend starting from the beginning.

Pananma Wilt

Symptoms are yellowing of lower leaves, including leaf blades and petioles.

Natural Control

  • Severely affected plants should be uprooted and burnt.

Other Control Options

  • Consult County Extension Agent

Leaf Spot

Appears as light yellowish spots on the leaves, small number will enlarge, become oval and color changes to dark brown. The center of the spot dies turning light grey surrounded by a brown ring. Severe case can kill the large parts of the leaf.

Natural Control

  • Serenade® Garden Disease Control
  • Good drainage, weed control, correct spacing is recommended and removal of diseases suckers.

Anthracnose

Appear as large brown patches covered with a crimson growth of the fungus. Fruit turns black and is shriveled.

Natural Control

  • Serenade® Garden Disease Control

Crown Rot

Blackening of the crown tissue spreads to the pulp through the stalk resulting in rotting of the infected portion and separation of the fingers from the stalk.

Natural Control

  • Serenade® Garden Disease Control

Aphids

They are the size of a pinhead and vary in color depending on the species. Cluster on stems and under leaves, sucking plant juices. Leaves then curl, thicken, yellow and die. Produce large amounts of a liquid waste called “honeydew”. Aphid sticky residue becomes growth media for sooty mold.

Control

  • Consult County Extension Agent

Banana Weevil

Adult weevil is about ½ inch long with hard shell and small snout protruding from their heads. Female lays eggs in holes at the base of the plant. Weevil does damage by burrow and tunnel into the plant roots and stems.

Natural Control

  • Trim any weak or damaged plants and remove any dead plant debris from the soil.
  • Mulch around the base of plant will help prevent females from laying eggs.

Other Control Options

  • Consult County Extension Agent

Mites

Pinpoint size, many different colors. Found on undersides of leaves. Sap feeding causes bronzing of leaves. Severe infestations have some silken webbing.

Natural Control

  • A strong stream of water from your garden hose can help control mites and keeping plants properly watered.

Other Control Options

  • Consult County Extension Agent

Nematodes

Small worms that feed on roots and foliage depending on the insect. Root feeder burrow into the root system and eat the roots causing reddish-brown lesions, leaves will turn brown and wilt. Foliage feeders produce lesions on leaves.

Natural Control

  • Remove and destroy infested plants, plant resistant varieties.

Other Control Options

  • Consult County Extension Agent

In This Series

  • Introduction

Getting Started

  • Acclimate
  • Location
  • Planting
  • Soil Preparation

Care & Maintenance

  • Fertilizing
  • Pest & Disease Control
  • Pruning
  • Spraying
  • Watering

Other Topics

  • Harvesting

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