Lace Bug update August 24

  • Posted on: 29 August 2024
  • By: ibuchanan

It's the end of August. and we have finally had some rain in the last few weeks. I had hoped to prune my trees and provoke some new growth, but with the lack of rain it hasn't happened.

Normally flowering is in October. Given the trees are just starting to recover now, it would be very optimistic of me to expect the trees to put their effort into flowers, so at this stage I have assumed we will not have a crop again next season. To put that into context....my evergreen olive trees lost their leaves to Lace Bug by March. Its now almost September, and some are just starting to show some new leaves after being bare for 6 months.

I have been pruning, some trees quite harshly and they will take two years to recover, anyway. I lost momentum with the lack of rain, so haven't done anywhere near as many trees as I wanted. I did commit to paying an arborist crew to do some pruning to speed up the process, but they mucked me around and in the end didn't do the work. (They did mulch the prunings I did, and we produced more than 30 cubic metres of chipped olive wood!)

I have also been liming my olive paddocks. Our soil across the farm is acidic, and although I have had contractors in liming the grazing paddocks, they don't want to push their trucks through the olive grove. So, the last week I have been doing it myself, with a small tractor, a spreader and pelletized lime in 20 kg bags. Its hard work....the bags come in one ton pallets. I get them forked onto my car, then have to manually unload at my end. I stack them out in the paddock at strategic intervals, then drive around with the tractor, and manually load up the spreader. By my count I am moving each bag at least twice, sometimes more. Three paddocks done, one to go. Only another 1.5 tons to go....

It is hard work, but its actually one of the smoothest agricultural tasks I need to do. Now that we've sorted out the logistics I will do it again next year, incrementally improving the soil ph over time. Olive trees that are unhealthy are more susceptible to insect attack, so by improving the soil/environment the trees are in we improve their ability to resist.

The worst affected trees have also been boosted. Each week I show up with 20-30 20 litre buckets of horse manure, collected from a farm down the road. The saddest looking trees get a 20 litre bucket each. I haven't seen much change on the trees, but the grass around the trees has exploded in growth!

I did promise to set up some insectaries to provide safe habitat for predator insects like Lacewing. Hasn't happened yet, although I have bought the trees/shrubs and they are sitting wafting to be planted out. The hold up is building a cow-proof enclosure so they don't get smashed to pieces. I did release a few thousand Lacewing larvae into the grove but they disappeared without a trace and I have yet to see an adult Lacewing.

The industry association appears to have taken on how bad Lace Bug was this last season, after initially ignoring it. I have seen some odd things though. One was a newsletter saying it was OK to spray your olives with insecticide the day before harvest! The other was a comment on the general lower crop volume this year, which seemed pretty misinformed: "SA has had a bad year, the Hunter Valley had a bad year, but other parts of New South Wales and Victoria have done reasonably well."

The media coverage has been mostly well-informed, and there are some links to these articles below.

There was a particularly annoying "story" which was a rehash of a Woolworth's puff piece. The basis of it was that "harvest conditions has improved" so we could expect a drop in olive oil retail prices soon. Just stupidly ill-informed, or deliberately misleading. Olives in Australia ripen around the same time, there's no ongoing season throughout the year. Its either a good season or not, and the season is over. There's nothing left to improve. I expect they are also factoring into it the possibility prices will decline because there might be a better harvest in Spain this year, but I wouldn't bank on it...there's a lot of catching up to do in Spain, and Italy is again having a disastrous run.

One of the things though that I think has been missed In Australia by those who were not in the eye of the Lace Bug storm was the volume of insects this year. Because there were so many they started moving to other trees, and we documented large numbers of Lace Bug on Ash, Privet and Pawlonia trees. Why this is a big deal is....to get from one olive grove to another might mean hitching a ride 5 km down the road. (Although all my neighbours have at least one olive tree and all were carrying Lace Bug this year.) But with Lace Bug feeding on other trees, they were able to leapfrog more easily...there is an Ash/Privet/Paulownia every 100 metres or less in the Alpine Shire...in gardens, along the road, in parks.....and no one is tackling insect invasions of these trees.

We have had a cold winter in north east Victoria, although most of the news is about how its been a warm winter. Winter has finished earlier for us, but we had some 6 weeks of frost almost every night. Some nights the frost started at 10pm and went through until morning. I had vegetables frozen in my greenhouse. So I was quite depressed to find live Lace Bug sunning themselves on the end of a low branch on the first warm sunny day we had, about three weeks ago. Since then, however, we had two more frosts of -3 degrees, and I haven't found a live Bug since.

Having said that, it doesn't mean there aren't eggs already planted, sleeping, waiting for warmer weather. I've started talking to the chap who blast-sprayed the grove last year, and I expect I will need to do that in September.

Some interesting news items about Lace Bug

ABC on Olive Oil prices due to poor crop

SBS News story on Lace Bug 27 August 2024

Agriculture Victoria reference on Olive Lace Bug