Bananas’ most important nematode infection globally is the burrowing nematode, Radopholus similis. The burrowing nematode is one of the most strictly controlled nematode plant pests. Burrowing nematode infection results in toppling disease in bananas that destroys root tissue, leaving plants with little to no support and a reduced capacity to absorb water and transfer nutrients. Dark and necrotic lesions on the root system are the easiest way to spot burrowing nematode symptoms. Similar to those brought on by Helicotylenchus multicinctus. (11)
Most nematicides are challenging to be used, particularly if they need soil injection or are fumigants. Many are expensive, frequently applied, and hazardous to people. They are not advised for smallholders for these reasons, in addition to the fact that they harm the ecosystem by destroying all soil organisms. Pre-plant treatments of banana plants and/or soil are important to reduce or delay the effects of the burrowing nematode on the crop. (12)
Aphid (Pentalonia nigronervosa)
Tiny oval-shaped aphids with a reddish brown to practically black color. Forewings on wing forms are prominent and contain veins that are darkly colored. Two distinctive extensions from the back of the abdomen are a feature of aphids. On the pseudostem (of banana plants), behind the leaf bracts and between the bunch bracts and the branching stalk, are colonies of the adult and immature stages. Moreover, colonies can be found under leaf bases near the ground or in the top unfolded leaves of young plants and suckers. Direct feeding harm is rare. Excessive honeydew damage and sooty mold growth occur only when populations reach large levels. Bunchy top control cannot be achieved with chemical aphid control, and direct damage is rarely severe enough to require treatment.
Flower Thrips (Thrips hawaiiensis)
On the surface of newborn banana fruits, little, slender-bodied energetic insects are frequently observed moving, especially close to the “bell,” or male end, of the fresh bunch. Mature females are 1mm long, clearly colored brilliant orange and black, and are typically found inside or under bracts of flowers. Males (0.75mm) are typically found on the outer surface of the bracts and are a light straw color. The distinctive translucent wings of adult thrips feature a fringe of hairs around the outside edge that protrudes in the same plane as the wing. Using an x10 hand lens, they are clearly visible. Bud injection with insecticide to control.
Fruit Caterpillar (Tiracola plagiata)
The wingspan of an adult moth is between medium and big, measuring 50 to 60 mm. With a dark brown V-shaped patch on the fore-edges, the darker forewings are dull grey-brown in color. The hind wings are a consistent light brown-gray color.
Larvae feed both with fruits and leaves. While smaller, younger larvae feed on the rind of immature fruit, larger larvae bore deeply into the fruit, leaving irregularly shaped brown spots of damage on exposed fruit surfaces. One or two larvae can completely damage the fruit on the bunch because of their size. Compared to banana scab moth damage, which is typically shallower and limited to the underside of the fruit where it joins the bunch stem, the damage is more severe and obvious.
As bunch treatments to control rust thrips and sugar cane bud moth provide adequate control of banana fruit caterpillar, no additional controls are typically needed.
Rust Thrips (Chaetanaphothrips signipennis)
The adult’s body is 1.5mm long, creamy yellow to a golden brown, and has finely feathered wings. The adult thrips’ unique longitudinal black stripe extends from the black hairs that make up the front margin of the wings along the middle of its abdomen. At the base of the wings, the mature rust thrips have two dark spots that mimic eyes. These patches can be used to identify the male banana flower thrips, which are smaller.
Feeding during the adult and nymphal periods causes damage. Early warning indicators include wet, smoky areas where colonies congregate to feed and lay their eggs next to or around the fruit. These areas then exhibit the typical rusty-red to dark brown-black staining.
Both the adults and larvae on the fruit and plant, as well as the pupae that live in the soil, should be targeted for chemical management. Continuous reinfestation will occur if the pest is not controlled at both locations, especially during the hot, humid times of the year.
- Treatments for the soil: The rust thrips will be temporarily under control thanks to the treatments for the banana weevil borer in September and October.
- Fruit and plant treatments: A pesticide should be put on all bunches, the pseudostem, and the suckers. Use caution, as this pest management strategy can disrupt beneficial insects.
- Treatments for bunches: Scab moth pesticide injection offers early bunch defense against rust thrips. After that, you should apply one pesticide to the bunch or apply the required length of SusCon ribbon at the same time you apply the bunch cover to extend protection up to harvest.
Banana Spider mite (Tetranychus lambi)
The banana spider mite is the most prominent and widespread of the banana mite pests.
Adults normally have 8 legs, are less than 0.5mm long, and are hardly visible to the human eye. The banana spider mite and the two-spotted mite are similar. The banana spider mite appears straw-colored and lacks markings. The main distinction between the two species is that infestations of banana spider mites lack delicate webbing. Extreme breakouts, however, could result in the mites moving onto the bunches and damaging the fruit. Generally, only the lowest, older leaves are destroyed. Along the leaf, rusty patches that were initially separate from one another eventually merged.
Action levels have not yet been established; however, if young leaves are found to contain mites and dry to hot weather is predicted, treatment should be used to stop harm. When used early in an infestation, miticides are most effective.
Spray only when plants are not under heat or moisture stress because it is difficult to cover the mites on the underside of leaves when leaves are wilted. Avoid exceeding prescribed rates and quantities to avoid fruit “burn.” You can accomplish effective mite control by employing properly calibrated sprayers or misting devices and timing your miticide applications. To provide good coverage of the leaf undersurfaces where the mites live, a sufficient amount (up to 500 L/ha) must be administered. In most cases, a second treatment should be used 14 days after the first.
Banana Scale Insect or Coconut scale (Aspidiotus destructor)
Plant tissue is yellowed and discolored locally as a result of this bug. It is categorized as an armored scale; feeds in circular colonies on the underside of banana leaves; and can cling to fruits, petioles, and peduncles. All stages of the plants are susceptible to damage. Plants become stunted due to attacks on pseudostems, leaf petioles, and leaves. Severe attacks can kill the infested banana plants. Tree damage results in leaf loss, plant stunting, and plant dieback. Fruit bunch infestation results in fruit that are malformed and unsellable. Fruit with scale insects present have flaws, are malformed, and cannot be sold. The growth of sooty mold on plant surfaces, particularly on leaves, is a secondary impact of the CSI that reduces photosynthesis. Ants are attracted to sweet excretion, which helps spread the insect pest.
Sprays of insecticidal oils are used to get rid of scales. Ants take care of these insects and eat the honeydew that they create. The long-term fix for CSI is biological control. Introducing natural enemies reduces the pest population in nations where the scale is prevalent. Other scale insects’ natural predators may evolve to eat A. destroyer as it expands its colony. A small number of specialized and numerous non-specific parasitoids and predators prey on the scale. The coccinellid beetles, including Chilocorus spp., Cryptognatha nodiceps, Pseudoscymnus anomalus, and Rhyzobius spp., are the most prevalent. Although research on and knowledge of parasitoids are lacking, Aphytis spp. and other Encarsia species greatly contribute to keeping the insect populations under control in the field. (15)
- Aguayo, J., Mostert, D., Fourrier-Jeandel, C., Cerf-Wendling, I., Hostachy, B., Viljoen, A., & Ioos, R. (2017). Development of a hydrolysis probe-based real-time assay for the detection of tropical strains of Fusarium oxysporum f. sp. cubense race 4. PLoS One, 12(2), e0171767
Banana Plant Protection – Common Pests of Banana Plants