Snail Managgpement and Research Update
SARDI Entomology Helen DeGraaf Pest Facts SA & western Victoria Edition
• FREE electronic newsletter produced for growers and advisors on an as-needed basis throughout the winter season
• Regular updates on invertebrate pest issues in broad acre crops • Pest warnings, management information • A way to detect regional pest issues early and highlight the need to check crops
• www. sardi. sa. gov.au/pestfacts • [email protected] • [email protected]
• (08) 8303 9370 The Battle Plan
• The Enemy • New weapons research • The Battle Front ¾ Biological warfare • Tactics ¾ Improving bait performance • Biosecurity ¾ Novel approaches
The Advertiser, 26/9/12 The Enemy
Round:
Vineyard or common white White Italian snail Cernuella virgata Theba pisana
CilConical:
Small conical snail Conical or pointed snail Cochlicella barbara Cochlicella acuta The Enemy
And now 2 more pest species?
• Small brown citrus snail in grain from western Eyre PiPeninsu la • Usually associated with citrus orchards
Small brown citrus snail
• Green snail established in Perth for 30+ years • 2011 discovered in Victoria (Cobram area)
Green snail The Enemy
Reproduction:
• Over-summer on elevated positions (pointed snails can over-summer under ground) • Autumn rains trigger activity • Feeding and maturing for 2 weeks Æ mating Æ laying eggs • Start of egg laying is determined by soil moisture • Hermaphrodites, every snail can lay 400 eggs!
To monitor for egg-laying:
• Look early in the morning • Snails on soil surface with foot inserted into topsoil • Eggs laid in clusters in shallow holes
•Hatching after 2 weeks The Battlefront
• 2010 and 2011 saw a major increase in snail activity, including early-season activity, densities and damage
• Primarily related to wetter (& cooler) summer/autumn conditions
• 2012 has seen residual high numbers and considera ble s lug ac tiv ity
• Longer-term farming system trends may be influencing snail impacts The Casualties
• Major increase in baiting programs = higher $$ inputs
•Croppgy damage and yield loss
• Harvest costs: ¾ some crops left unharvested ¾ clogging damage, header modification ¾ grain cleaning costs
• Delivery rejection or grain value dddowngrade ¾ contamination, grain discolouration Key Tactics
• Know your problem species and understand their behaviour (e. g. over-summering location)
• Use an integrated approach . The ‘silver bullet’ has yet to be discovered!
• Aim to reduce snail numbers prior to egg laying
• Monitor live snail density before and after treatments
• Reduce weeds over summer
• All year round consider opportunities to nail the snails! War games - Bashing
• Cabling, rolling, slashing
• Cabling is best bet where surface stones exist (beware ironstone)
• Bashing is most effective when surface temp over 35°C
• Overnight moisture, summer weeds and heavy surface mulch reduce mortality
• Repeat treatments increase mortality War games - Burning
100 • A slow, hot burn can be 80-90% 90 of effecti ve on round snail s ee 80 70
60
• Consider erosion risk & nutrient percentag pulation
ss 50 oo Pre burn loss 40 Post burn 30 initial p 20 • Controlling summer weeds first ive snails a ll substantially improves kill % 10 0 Burning only Desiccation • Protect burnt and snail free areas and burning from reinvasion (modified from Bash’em Burn’em Bait’em)
• Less effective against conical snails (shelter under rocks and below ground) War games - Baiting
• Timing is critical to stop egg-laying
• Snails must be active; cool & moist conditions following application
• It’s OK to bait before rain
• Populations >80/m2 will need multiple applications and higher rate.
• Remember to bait fencelines and scrub lines
• Kill summer and brassica weeds
• Finish baiting 8 weeks before harvest Snail management resources
Download copies from GRDC Media Centre Bookshop website LOOK OUT FOR GREEN SNAIL (Cantareus apertus – formerly Helix aperta)
• Native to southern Europe and North Africa – Established in the Perth area (WA) in the 1980s – Found in Vic (Cobram area) in 2011.
• Description: – whitish flesh with olive green shell (up to 25 mm shell diameter Juvenile green • Over-summers undththilfderneath the soil surface (15-150 mm snail (top) depth) Common garden snail (bottom)
• Wide hos t range: – wheat, lupins, pasture grasses, fodder (hay),beans, peas, vegetable crops (e.g. cabbage, cauliflower, lettuce) and native plants
• If you suspect you have found green snail, please contact Photos courtesy Dept of Primary Industries, Victoria. Biosecurity SA or call your Exotic Pest Hotline immediately on 1800 084 881 Key biosecurity practises around movement and hygiene include:
1. Restrict movement of machinery, equipment and produce (e.g. hay- bales) from entering property until inspected 9 This will help to reduce the risk of bringing more snails onto property 2. Clean all machinery and equipment to dislodge snails before moving • Use high pressure cleaning • have a designated clean down facility / area 3. Erect a farm gate biosecurity sign • demonstrates your commitment to cleanliness and safety 9 Ensures visitors contact you before entering any paddocks where there is a greater risk of spreading pests
Photos courtesy ; PIRSA, M. Richards, SARDI Entomology and DPI Vic. More information on green snail: http://www.pir.sa.gov.au/biosecuritysa/planthealth/emergency_plant_pe sts/green_snails
For a ‘free’ biosecurity farm gate sign contact: JdJudy BlltiBellati South Australian Grains Biosecurity Officer (08) 8207 7843 or 0412 218 228 [email protected] New weapons research
Biological warfare: - Nematodes Novel approaches: - PERLKA® fertiliser Improving bait performance: - Low biuret urea - Juveniles - Caffeine - Bait size Biological warfare
• Nematodes in association with specific bacterial isolates have proven effective in killing snails in laboratory trials – Charles Sturt University
• Nematodes enter the snail gut where they release lethal bacteria which kill the snail
• The nematode then feeds and breeds within the rotting snail Biological warfare
• Pathogenicity testing to find most lethal combinations of nematode and bacterial isolates
• In laboratory conditions, some combinations cause 100% mortality in all 4 snail sppyecies within 8 days
• Field conditions do not generally favour nematode survival ¾ low humidity ¾ soil type ¾ UV rays ¾ temperature
• High volumes of water are required at application Biological warfare
• The 1st SA field trial was in Sept 2011 in a lentil crop, Warooka. • Treatments were: ¾Bait (registered rate) ¾Low and high rate of nematodes (4,500 L / ha) ¾Untreated control • Assessed live conical and white snails on (i) ground and (ii) lentil plants at four post-treatment dates (7, 13, 28 and 34 DAT) • For one of these assessments (live conical snails on ground at 13 DAT) there was a significant nematode treatment effect
70 a 60
50 e snails
vv 40 30 b b b 20 umber of li
NN 10
0 Control Bait Nematode Nematode Low High Biological warfare
Experiment 1: May 2012, Warooka
• Promising nematode/bacteria combination applied at 900L/ha (nematodes diluted in water)
% Mortality Round snails Conical snails Control 7.0 9.5 Bait (Meta) 94.7 91.0 Nematode 5.5 20.1
• Very disappointing results may be due to: ¾ incompatibility ¾ environmental conditions ¾ formulation problems ¾ transport and shipping Biological warfare
Experiment 2: September 2012, Warooka
• 2 potential nematode/bacteria combinations applied at 4,500L/ha (nematodes diluted in water)
% Mortality Round snails Conical snails Bait (()Meta) 83.3 77.9 Nematode 1 15.4 44.7 Nematode 2 15.9 12.6
• Problems that need to be overcome: ¾ desiccation (improve formulation) ¾ application method (too much water) Baiting research - Juveniles
Baits only kill adults snails?
• Comparing bait products and mortality of juveniles (all 4 species)
• Experiments took place at Roseworthy under field conditions in August 2012
• Juveniles (<7mm) were collected from Warooka
• 160 arenas were prepared with snails and bait and assessed after 1 week.
• All snails were retrieved and assessed for mortality in the lab. Baiting research - Juveniles
• 60% mortality of common white juveniles
• Pointed snail mortality may have been inflated due to limited dead plant material (favoured h ost) i n arenas
100 Average morta lity btbetween jiljuvenile 90 snail species (all baits combined) 80 70 Arenas contained: 60 • brome grass 50 • stinging nettle
mortality 40 • canola % 30 20 10 0 White Italian Common white Small pointed Pointed Baiting research - Juveniles
Bait effects on juvenile snail mortality (all 4 species combined), n = 5 100 90 80 70 60 ality tt 50 40
% mor 30 20 10 0 Meta Slugger Slug Out Slug Off Metarex Multiguard Mesurol
A. I. 15g/kg 15g/kg 18g/kg 30g/kg 50g/kg 60g/kg iron 20g/kg met’hyde met’hyde met’hyde met’hyde met’hyde chelate methiocarb A. I. 9.4 13.2 16.9 9.5 32.2 76.4 12.2 ((/mg/m2) # baits 44166864 Baiting research - bait size
• Variable mortality between treatments may be a reflection of bait size (i.e. how many pieces on the ground – frequency of interception)
• Field arenas were set up to test the effects of bait size and rate on snail mortality
• Results are yet to be compiled, trials underway on slugs in Vic. Novel approaches – PERLKA®
• Granulated calcium cyanamide
• Used as fertiliser (nitrate) in horticulture, mostly Europe
• Described as a “multi-functional fertiliser”
• Claimed to have fungicidal, herbicidal and insecticidal properties
• Also cl a ime d to be tox ic to sna ils (a ll ages ) an d snail eggs
• GRDC funded trial
SARDI conducted 2 experiments: ¾ Egg mortality lab trial ¾ 2 large scale field trials Novel approaches – PERLKA®
• White Italian snail eggs were collected at Warooka, Yorke P. • 45 eggs per dish • Light rainfall event simulated every 2-3 days • Hatchlings were recorded for 34 days
Stocking material over Soil surface with container PERLKA® granules Cluster of snail eggs Drainage hole
4 dishes per Treatment Percent eggs hatched ±SE (Actual) treatment Control 25.0 ±7.72 (11.25 ± 3.47) 200kg/ha 0 (0) 400kg/ha 0 (0) 600kg/ha 0 (0) 800kg/ha 0 (0) Novel approaches – PERLKA®
• Canola and pasture field trials at Warooka. • Clt6Canola at 6-lftleaf stage t o recover f rom b urn/t /tiitoxicity • Control vs 250kg/ha (recommended rate)
40m
PERLKA PERLKA 40m
PERLKAPERLKA PERLKA
• Pre-treat ment snail count s, 5 quad rat s (50 cm x 50cm ) per p lo t • Post-treatment snail counts at 9 weeks, 5 quadrats per plot Novel approaches – PERLKA®
Results • Juvenile snails accounted for majority of snails pre and post treatment.
•Majjyority of snails were the White Italian and Pointed snails
Average number of juvenile snails (all species) per 2500cm2 (¼ m2) Canola Pasture Pre-treat Post-treat % change Pre-treat Post-treat % change Control 38.2 a 178.8 a ↑ 468% 497.4 a 634.6 a ↑ 128% PERLKA® 28.2 a 113.4 a ↑ 402% 333.0 a 471.2 b ↑ 142% Tukey’s test • Results are less than impressive, but may reflect patchiness in field. Novel approaches – Low Biuret Urea
• LbLabora tory pil ilttilot trials s howe d prom ise
• Field trial set up at Warooka, YP to test toxicity effects of Low Biuret Urea on snails
•Repppglicated plot design in a wheat ,p, each plot 30x30m
• Treatments ¾Urea 10kg/ha (applied in solution 50L/ha) ¾Urea 20kg/ha (applied in solution 50L/ha) ¾Water only (50L/ha)
• Post treatment assessments occurred this week Novel approaches - Caffeine
•Syypnthetic caffeine solution to kill/repel snails away from crops at harvest time
• Trials planned in peas and windrowed canola
• Pure synthetic caffeine is dissolved in water with sodium benzoate to improve solubility
• Residue analysis in harvested product
• Registration hurdles Acknowledgements
SARDI: Greg Baker Latif Salehi Sarah Mantel Mark Barrett Kym Perry
Graham Hayes (farmer, Warooka)
Charles Sturt University: PfGiAhProf. Gavin Ash Dr Aisuo Wang
Michael Richards (NRM)
GRDC & Southern panel members Grain Pest Resistance Project
• cesar at The University of Melbourne
• Aim to build a database of chemical resistance in croppp pest s pecies Australia wide – Early warning system
• Focus on earth mites and aphids, and bioassay to determine levels of resistance
• ClltCollect represent ttiative popu ltilations throughout the states
• Respond to all incidences of resistance for all mite and aphid pests Grain Pest Resistance Project
If you suspect a chemical failure for any mites or aphids in any crop, plltk!lease let us know! cesar can arrange a FREE resistance test and provide assistance with recommendations for control.
Helen DeGraaf SARDI Entomology 8303 9543 [email protected] Remember....
• Know your problem species and understand their behaviour (e.g. over-summering location)
• Use an integgpprated approach. The ‘silver bullet’ has y et to be discovered!
• Aim to reduce snail numbers prior to egg laying
• Monitor live snail density before and after treatments
• RdReduce weed s over summer
• All year round consid er opport uniti es t o nail th e snail s!