Detection and Monitoring of Stored-Grain Insects
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Transcript Detection and Monitoring of Stored-Grain Insects
Detection and Monitoring of
Stored-Grain Insects
Bh. Subramanyam, Carl Reed, and Phil
Sloderbeck*
Department of Grain Science and Industry
*Department of Entomology
Kansas State University
Manhattan, KS 66506
[email protected]
2006 Grain Handlers Workshop
Detection
Looking for presence or absence of an
insect or an infestation (with respect to
your sampling device)
The type of device used and the number
of samples taken determine how good
you are in finding an insect or an
infestation
Monitoring
Tracking trends in insect numbers or
infestation levels over time
Helps you know when to take action
Helps you understand how populations
are behaving with respect to
environmental conditions
Helps you assess effectiveness of pest
management actions
Detection and Monitoring Require
Sampling
Counting all insects in a bin is difficult
Their distribution is unknown
It may take forever to count all insects
present
Time and money are limited
Sampling will help in making inferences
about the insects inhabiting a bin or silo
Infestation in Railcars
Wheat
21, 3 kg wheat samples/railcar were taken from 8
railcars (Perez-Mendoza et al., 2004)
They also had a lot of IDK
1024 insects were found in 7 of 8 railcars
3% of insects were found immediately after sample
collection
77.1% were found 7 weeks after sample incubation
Relevance to detection??
Relevance to fumigant efficacy??
In Concrete Elevators
High insect density is within the top 3-4 ft and all of
the insects can be found within 40 ft from the top
Discharge from spouts onto reclaim belt had more
insects than grain samples taken with a vacuum probe
Fewer insects were found in treated empty bins and
the treatment effectiveness lasted 12 weeks
Relevance: Understand where to sample!
Grain Sampling Methods: Absolute
Estimates
Diverter-type
sampler
Pelican
Ellis cup
Grain trier
Vacuum probe
Scoop
Diverter
Pelican Sampler
Ellis Cup
Grain Bulk
• Probe sampler
• Spear or trier
Vacuum probe for
bulk-stored grain
Insectomat
Capable of processing
large samples
Pass grain sample twice
for extraction of all
insects present (need to
check efficiency in
separating insects from
grain)
Torpedo (spear) sampler
Coning and quartering
Boerner divider and other
dividers (sample reduction)
Sieving (check efficiency)
Bagged Grain
Torpedo Samplers
Sieve Samplers
Inclined
sieve
Dividers
Absolute Estimates Are…
More reliable estimates
Pest management decision should be based on
absolute estimates
Threshold for management: 1 insect/kg
Time consuming, laborious, and expensive
Insect Sampling Devices: Relative
Estimates
Number of insects found in a trap
constitutes a relative estimate
There are many trap types
Sticky traps for
flying insects
For almond moths and
Indianmeal moths
Pherocon II traps
Pheromone lure
Traps for Crawling Insects
Provides a hiding place
Includes various designs
Can be used with pheromone lures or food
baits to enhance capture of species
Can capture multiple species
Corrugated Harborage Traps
Corrugated
Paper Traps
Bait-Bag Traps
Netlon netting (8x16 cm)
Aperture 2 mm
Brown rice-60 gram
Food-baited Traps
Traps for Use in Bulk-Stored Grain
Perforated metal or plastic probes or cones
inserted into grain bulks
Insects crawl through the holes and fall into a
collection tube or cone
Pitfall Cone Trap
95 mm x 125 mm
cone-shaped
with holes
Very sensitive
For surface area
of the grain bulk
Probe traps
370 mm x 27 mm
Funnel and collecting tube
Can be inserted into the
grain bulk
Trap Retrieval is Critical!
Automated counts of insects in grain
(OPIsystems.com)
Stormax Insector
150
(a)
Flat grain beetle (n=2105)
Rusty grain beetle (n=1284)
Sawtoothed grain beetle (n=1620)
Lesser grain beetle (n=1387)
Numbers of Insects
100
51.3 cm
(b)
Red flour beetle (n=2432)
Rice weevil (n=1834)
50
(c)
(d)
0
0
10
20
30
40
50
60
70
80
90
100
Composite Adjusted Target Peak Amplitude
OPI Systems, Calgary, Canada
110
120
Relative Estimates Are…..
Faster, cheaper, and easier than absolute methods
Traps work 24 hours a day, 7 days a week
Interpretation of numbers is difficult (biological and
environmental variable affect insect captures)
Can be used to pin point problem areas
Can be used to evaluate effectiveness of pest
management measures
Take Home Points
Be a truck, railcar, bin, or elevator silo
Take more samples than fewer samples
More than 10 and less than 30
Information from sampling can be used in 2 computer
programs (SGA and SGA Pro) to make pest
management decisions
Without proper detection and monitoring of insects
you will treating more number of times than needed
or fail to treat when you really need to!