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 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)

Bagged Grain  Torpedo (spear) sampler  Coning and quartering  Boerner divider and other dividers (sample reduction)  Sieving (check efficiency)

Torpedo Samplers

Sieve Samplers Inclinedsieve

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

(a) (b) (c) (d) 51.3 cm OPI Systems, Calgary, Canada

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!