Pests

Question 1

Phylloxera
(describe, symptoms, management)

Answer 1

An aphid-like insect that feeds and lays eggs on the roots of grapevines, damaging roots and the plants ability to uptake water/ nutrients as well as making the vine vulnerable to infection. This weakens the plants growth and yield, ultimately killing the vine.

Symptoms:
1) vines die of drought in increasing patches year over year
2) roots covered in insects and yellow eggs
3) swellings on older roots
4) pale leaf galls under leaves
5) 3 years, slow stunted shoot growth and leaf yellowing
6) 5 years, death

Management:
1) use of American rootstock such as V. Berlandieri, V. Riparia, & V. Rupestris

Question 2

Nematodes
(describe, symptoms, management)

Answer 2

Microscopic worms that feed on vines roots, reducing yield and vigour and possibly spreading viruses. The most common are root-knot and dagger nematodes. They are either already present in the soil or spread by unclean nursery stock, irrigation, or vehicles.

Symptoms:
1) reduced yield and vigour

Management: (once present can never be eliminated)
1) fumigate soil via traditional chemicals, largely banned, or by ploughing in mustard plant
2) resistant rootstocks like Ramsey or Dog Ridge

Question 3

Grape Moths
(describe, symptoms, management)

Answer 3

These moths feed on flowers and grapes making the vine vulnerable to attack from bacteria or fungus which can cause serious losses. Many moths have multiple generations throughout the growing season, making them extra detrimental.

Symptoms:
1) evidence of damage on flowers and grapes

Management:
1) biological controls (Bacillus thuringiensis or pheromone capsules)
2) introduce natural predators (parasitic wasps, green lacewings, spiders)
3) insecticides

Question 4

Spider Mites
(describe, symptoms, management)

Answer 4

Spider mites feed on the surface cells of leaves, causing reduced photosynthesis, delayed ripening, and a reduction in yields. Many mites exist but spider mites are the most detrimental towards vines. Notably the pacific spider mites feed of California and the red/yellow spider mites of Europe. They thrive in dusty conditions and are most detrimental on water stressed vines.

Symptoms:
1) discoloration of leaves
2) reduced photosynthesis
3) delayed ripening
4) reduced yields

Management:
1) using sprinklers or cover crops to reduce dust
2) encourage predatory mites by planting host species
3) pesticides

Question 5

Leafhoppers

Answer 5

Damage to vine leaves

Question 6

Ladybirds

Answer 6

Caused taints if harvested with grapes

Question 7

Birds

Answer 7

Birds can destroy an entire crop of grapes, often Starlings.

Management:
1) netting
2) bird scarers/ noise machines
3) falcons

Question 8

Mammals

Answer 8

Mammals eat shoots, grape, and leaves making the vines vulnerable, reducing yields, lowering quality, and possibly damaging trellising which is expensive. Deer, rabbits, kangaroos, raccoons, wild boars, and baboons.

Management:
1) fencing