Tuesday, September 24, 2013

Notes on Spring Pest & Disease levels.


Vines are now getting out to 4-6 leaves separated with shoots nearly 20cm long in some cases. This week gave us the first opportunity to see the ‘major’ pests and diseases. We commercially monitor for pest and disease vineyards near abandoned Chardonnay vineyards which are known hotspots. Currently these look clean. 

Over the next few weeks, as the weather has been favourable to powdery (warm, overcast and humid), the fungus is likely  break out of these vineyards earlier than last year. We will keep monitoring very closely to gain insight into what it is likely to do in the district as a whole.

Eutypa Dieback can now  be seen showing  up as foliar symptoms.

The  foliar symptoms of Eutypa lata in spring.

A Light Brown Apple Moth (LBAM) eggmass.
This week we also had the first detections of LBAM eggmasses – picture aboved. We are expecting to see levels higher than previously because of high levels of habitat in mid-rows and very obvious night-time flights of adults. Also seeing some adult cabbage moth and vine moth flights.

There are also high levels of Earwigs, Snails and in some cases Curculio Weevil. Look out for damage to young shoots.

Wednesday, September 11, 2013

Curculio Weevil Damage in Willunga - UPDATE 11/9/2013

A hollowed out bud suspected to be caused by Curculio weevil.
Growers are advised to be on the look out for weevil damage (buds hollowed out or shoots stripped of foliage as shown above). These symptoms can be be caused by garden weevil, which is a problem in Langhorne Creek and the Adelaide Hills, or Curculio weevil more commonly found in McLaren Vale.

Both Curculio weevil and Garden weevil emerge for the soil and at night and chew leaves and even whole buds. They are also known as Apple Weevil, or Apple Beetles.

This week some possible Curculio weevil or Garden weevil activity has been seen damaging vines (and olives) In some vineyards in the areas west of Willunga significant damage has occurred.

Both types of weevil are difficult to see during the day where they hide the soil. They can also shelter in bark during the day. Keep your eyes out.

Description

• Larvae - are soil dwelling, legless and have a brown head with black jaws. The
larva of apple weevil is similar to garden weevil, spotted vegetable weevil and
sitona weevil. A microscope is required to identify the actual weevil type in the
larval stage.

• Adult - medium sized about 8mm long and uniform brown weevil. It has a
slightly bulbous abdomen. The adult weevils are flightless and all are females.

Habits

• Adult weevils feed at night. They are inactive during the day and shelter under
bark, in the crotch of branches, between fruit and leaves, and burrow into soil
around the base of trees.

• When disturbed they fall to the ground and quickly walk away.

Life cycle

• Eggs are laid in loose organic matter on the soil and hatch in 10 - 14 days.

• Young larvae are mobile; they immediately burrow into the soil to feed on plant
roots.

• Larvae develop slowly during winter and more rapidly as soil temperature
increases in spring. They pupate in October/November.

• The length of the pupal stage depends on weather conditions. It usually lasts three
to four weeks.


If you are seeing these symptoms and need specific advice please contact us.