Black spot

Elsinoe ampelina (grapes - anthracnose), Alternari solani (tomatoes, capsicums and potatoes - target spot or early blight), Venturia inaequalis (apple and pears - apple and pear scab), Guignardia citricarpa (citrus), Xanthomonas campestris (mangoes - bacterial black spot), Phoma medicaginis var. pinodella, Ascochyta pisi (field peas - black spot complex)

A number of horticultural crops are challenged by black spot, which is also referred to by a number of names. It affects grapes where it is also known as anthracnose. Black spot affects apples and pears and is also known as apple scab and pear scab. In mangoes, black spot is caused by a bacteria rather than a fungus and is referred to as bacterial black spot. In broadacre, field peas are also affected by black spot.

Refer to the links below for more detailed information on black spot in each crop.

Description

With the exception of mangoes, black spot survives as sclerotia from the previous season’s infection and most commonly infects younger leaves and stems. Its development is most common in spring after rain which allows the fungal spores to spread and cause surface infection. In all instances, brown to black lesions result which can affect yield and fruit quality.

Control

Black spot is best managed by implementing a number of preventative measures to reduce the impact of the initial infection rather than trying to control the disease curatively. For each crop preventative measures differ, but will include;

Planting of disease-free seed

Rotate crops

Prune trees or vines to remove disease and improve air flow

Practice good orchard hygiene i.e. sterilise pruning tools, remove diseased fruit

Remove infected leaf litter and plant material

Apply preventative sprays.

Fungicides should all be applied before disease symptoms appear. Luna® Sensation and Flint® are registered for black spot control in apples and pears, Blue Shield® in apples, pears, mangoes and citrus. Blue Shield is recommended for the control of target spot (early blight) in potatoes and tomatoes. Antracol® is registered for black spot control in citrus and target spot (early blight) in potatoes and tomatoes. Aviator® Xpro® is registered for the control of black spot complex in field peas.

Related Pests

Black spot Grapes

Elsinoe ampelina

Black spot, also known as anthracnose in grapes, is a serious disease, particularly in areas which experience cool wet springs which favour disease outbreak. Currently it is successfully managed with fungicides, however prior to their introduction, blackspot was a major problem. Table grape varieties including sultana and red globe are more prone to black spot than wine grapes. Once established black spot is unrelenting and regular treatments are required to manage it.

Refer to links below for more information on black spot in other crops.

Black Spot Tomatoes and Potatoes

Alternaria solani

Black spot, also commonly known as early blight or target spot, is a serious fungal disease affecting vegetables belonging to the Solanaceae family. Disease hosts include tomatoes, potatoes, capsicums and eggplants. Outbreaks are favoured by warm, wet growing conditions and yield losses can be significant.

Refer to links below for more information on black spot in other crops.

Black Spot Apples and Pears

Venturia inaequalis (Apple scab), Venturia pirina (Pear scab)

Black spot, also known as apple scab or pear scab, is a serious disease found in pear and apple growing regions across Australia. Whilst symptoms in apples and pears are similar, the disease is caused by different fungi and cross infection from one host to the other isn’t possible. Leaves and fruit at early development are highly susceptible and serious yield and quality reductions are likely if not managed properly, especially in wet seasons.

Symptoms in pears and apples are very similar and therefore have been described as such unless otherwise indicated.

Refer to links below for more information on black spot in other crops.

Mango bacterial black spot

Xanthomonas campestris pv. mangiferaeindicae

Bacterial black spot (BBS) was first found in Australia in the early 1980’s and it now appears in most northern mango growing areas of Australia. It has the potential to be a serious disease of mangos, in some cases up to 90 per cent of fruit is discarded due to spots on fruit deeming them unacceptable for market.

Refer to links below for more information on black spot in other crops.

Blackspot of field peas

Mycosphaerella pinodes, Phoma mediccaginis var. pinodella, Phoma koolunga, Ascochyta pisi

Commonly referred to as ascochyta blight, blackspot is one of the most serious diseases of field peas and is widespread in Victoria and South Australia. In field peas, blackspot is produced by four different pathogens, producing symptoms that are indistinguishable from each other. Yield losses of up to 60 per cent have been reported, particularly in wet seasons.

Refer to links below for more information on blackspot in other crops.

References

Agriculture Victoria (2010), ‘Black spot of grapevines, http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/plant-diseases/grapevines/black-spot-of-grapevines

Doepel, R (1960), ‘Black spot of tomatoes, Journal of the Department of Agriculture, Western Australia, Series 4: Vol. 1 : No. 5 , Article 4,
https://researchlibrary.agric.wa.gov.au/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1716&context=journal_agriculture4

Herbiguide (Viewed October 2019) ‘Target Spot of Potato, Tomato and Capsicum’,
http://www.herbiguide.com.au/Descriptions/hg_Target_Spot_of_Potato_Tomato_and_Capsicum.htm

Pestnet (Viewed October 2019), ‘Pacific Pests and Pathogens - Fact Sheets: Mango bacterial black spot (213)’, http://www.pestnet.org/fact_sheets/mango_bacterial_black_spot_213.htm

Pitkethley, R (2006), ‘Agnote: Bacterial Black Spot of Mangoes’, Department of Primary Industry, Fisheries and Mines, https://dpir.nt.gov.au/__data/assets/pdf_file/0016/233611/605.pdf

Taylor, A and Gordon, C (2019), ‘Black spot of grapevines in Western Australia’, Department of Primary Industries and Regional Development (DPIRD),
https://www.agric.wa.gov.au/spring/black-spot-grapevines-western-australia?page=0%2C1