Grape phylloxera

Adults

• Small size (0.7–1.0mm).
• Oval shaped.
• Soft bodies.
• Vary in colour from green to brown or orange.

Nymphs

• Resemble adults but are smaller.

Eggs

• A female can lay up to 400 eggs (less than 0.3mm) at a time.
• Newly deposited eggs are lemon-yellow, oval, and about twice as long as they are wide.

Plant stage and plant parts affected

Phylloxera nymphs and adults infest grapevine plants during the vegetative growth stages. Depending on the strain of phylloxera, leaves and/or roots are damaged, galls are formed, and stunting and dieback of the whole plant occurs.

Plant damage

Phylloxera adults and nymphs feed on the grapevine roots. This leads to hook shaped galls developing on root hairs or rounded swellings forming on older roots. The galls hinder root growth, and reduce water and nutrient absorption by the plant. Galls and swellings are prone to secondary bacterial and fungal infections that lead to the rotting of grapevine roots, yellowing of the leaves and overall loss of grapevine vigour. Susceptible grapevines can die within 3–10 years.

Some strains of phylloxera can cause pea-size leaf galls on the underside of grape leaves. The leaf galling can cause leaf distortion and leaf fall, which can result in less fruit being produced. Leaf galling strains of phylloxera are not known to be present in Australia.

Leaf yellowing and general wilting symptoms can be produced by other causes of root damage or water stress, such as root rotting from fungal and bacterial diseases or drought.

Nematodes can also cause galling on grapevine roots. Nematode galls tend to be spherical in shape.

An expert is required to identify grape phylloxera. If you suspect the presence of grape phylloxera, you must report it to Biosecurity Queensland on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

Grape phylloxera is native to North America. It spread to Europe and then to many of the grape-growing regions around the world in the late 1800s, where it caused severe production losses. Vineyards had to be replanted with vines grafted onto phylloxera-resistant rootstock.

Grape phylloxera is present in Victoria and New South Wales. It is not known to occur in Queensland.

Grapevines (Vitis vinifera), with some cultivars more susceptible than others. Some ornamental and wild Vitis species have also been recorded as hosts, e.g. Vitis aestivalis (summer grape), Vitis labrusca (fox grape) and Vitis riparia (riverine grape).

• The life cycle of phylloxera is complex and can occur completely underground or alternate between above ground and underground reproductive cycles. The alternation of above and below ground life cycles is illustrated in the Murray Valley Winegrowers Phylloxera brochure (PDF, 2.4MB).
• To date there is no evidence of sexual reproduction in phylloxera in Australia. Only female phylloxera adults have been found and they can reproduce asexually.
• It only takes 1 phylloxera individual (egg, nymph or adult) to introduce this pest to your property.
• Each female can lay up to 400 eggs several times in a season depending on a variety of factors.
• The eggs hatch into nymphs soon after the plant breaks winter dormancy. These nymphs are known as crawlers and can move short distances (e.g. plant to plant).
• Crawlers are most abundant soon after bud break to the end of summer.
• The crawler stage lasts for 5–8 weeks depending on a number of factors including the environment.
• Small numbers of phylloxera can survive over winter underground on vine roots or under bark around the base of the grapevine.
• In very cold climates phylloxera produce a very robust form of egg to over-winter.
• By the time symptoms are visible, the insect may have been present for several years, but at a level that has been difficult to detect.

Australian grape production contributes significantly to Australia's economy, jobs and local communities, with about 1,000 growers producing table grapes. In 2015–2016 Australian table grape production was valued at $431 million with exports valued at $373 million. During the same financial year, over 5,000 wine grape growers grew grapes. Once made into wine at 2,300 wineries, export sales were valued at $2.56 billion in 2017. It is estimated that wine grapes contribute $40 billion to the Australian economy annually (Source: Plant Health Australia).

Phylloxera is a serious grapevine pest that has had a significant impact on grape production internationally, wherever susceptible grape cultivars are grown. Most commercial grapevines grown in Australia are highly susceptible to grape phylloxera, therefore preventing pest spread is critical for the industry.

There are no chemical or biological controls. Phylloxera control relies on complete removal of infested plants and replanting with resistant rootstocks, which is a costly exercise for affected growers.

The presence of grape phylloxera would have trade implications for fresh fruit and other plant product exporters and propagation nurseries within Australia and internationally.

Backyard growers of fruit producing and ornamental vines would also be affected.

Phylloxera can be present without the plant showing symptoms.

Movement of infested grapevine plant propagation material and other grape products used in winemaking such as fruit, unfiltered grape juice, marc and must (from pressing grapes) can spread phylloxera over long distances.

Phylloxera can also be spread in:

• plant debris
• soil
• packing material
• any equipment that has been in contact with soil or other growing mediums that has been in contact with infested grapevines.

The best time to look for phylloxera symptoms in Queensland vineyards is when populations are likely to be at their peak during spring and summer (September to March).

Look for weak or stunted vines with premature yellowing.

Phylloxera reproduces most easily on healthy root systems. Dead and weakened vines will often have low populations. If you suspect an infestation, check the border of the damaged area on vines that are just beginning to show signs of decline.

Carefully dig up a number of roots and inspect the new growth on the fine, feeder roots for galls (small swellings), which result from phylloxera feeding. Root tips infested with phylloxera are often club-shaped or form hooks. Galls may initially be white or yellow, but turn brown later as they mature.

A 10X hand lens or greater will be needed as the insects are very small.

If you suspect that your vines have phylloxera, call Biosecurity Queensland on 13 25 23. Do not attempt to move suspect grapevine material or soil samples.

The following important on-farm prevention measures can help protect your farm from grape phylloxera.

• Restrict visitors, vehicles and other equipment from vineyard areas, unless appropriate disinfestation procedures have been observed or plant health certification provided.
• Check that any grape plant, machinery, equipment or grape material from interstate is accompanied by appropriate certification. If a plant health certificate is not provided with the item, do not allow it onto your property and report it to Biosecurity Queensland.
• Ensure there is no soil or vegetation on equipment, machinery or footwear before it enters your vineyards.
• Place signs at the property's entrance outlining the basic biosecurity requirements to remind visitors and staff of their obligations.
• Record significant movements of risk items onto your property in a diary or log book and check your vines on a yearly basis for the presence of phylloxera.

Protect your farm from plant pests and diseases:

• Protect your farm from emergency plant pests
• Understand good farm biosecurity
• Visit the farm biosecurity website

There is currently no method or chemical available that will eradicate phylloxera from an infested vineyard. The only way to grow grapevines in a phylloxera-infested vineyard is to replant it with grapevines grafted to a resistant rootstock.

Grape phylloxera is prohibited matter under the Biosecurity Act 2014.

Report suspected grape phylloxera to Biosecurity Queensland immediately on 13 25 23 or contact the Exotic Plant Pest Hotline on 1800 084 881.

If you think you have found grape phylloxera, you must take all reasonable and practical steps under your control to minimise any associated risks. This is called a general biosecurity obligation (GBO).

Movement restrictions are in place to prevent the introduction of grape phylloxera into Queensland.

The nationally recognised Central Inland Queensland Phylloxera Exclusion Zone (PEZ) (PDF, 469KB) was created to protect Queensland's largest grape production area. A biosecurity certificate is required to move phylloxera carriers into this zone.

For more information on biosecurity zones and the restrictions that apply to them, see the Queensland biosecurity manual (PDF, 1.8MB).