Bale Compression and Hydrogen Phosphide Fumigation to Control Cereal Leaf Beetle (Coleoptera: Chrysomelidae) in Exported Rye Straw

Abstract

Control of larvae and adults of cereal leaf beetle, Oulema melanopus (L.), by bale compression and hydrogen phosphide fumigation was studied in rye straw, Secale cereale L., in Aurora, OR. Natural mortality of larvae after transport was 4.0 +/- 1.0% (mean +/- SEM). Compression (105 kg/cm2) of larvae in standard bales (122 cm long) of rye straw resulted in 100% mortality. Compression of adults in standard bales plus storage of the compressed bales (56 cm long) for 1 d in a freight container resulted in 100% mortality. A KD50 of 102 ppm hydrogen phosphide for 1 h was estimated from the probit regression line developed from dose-response data at 21 degrees C in basic laboratory tests. The LD50s and LD99s were 163 and 6,910 ppm for 2-h exposures and were 18 and 42 ppm for 6-h exposures at 21 degrees C, respectively. A tested close of 400 ppm for 24 h at 21 degrees C resulted in 100% mortality of the adults. Larvae (n = 10,560) and adults (n = 18,602) did not survive exposure to bale compression followed by hydrogen phosphide fumigation (60 g/28.3 m3) for 3 d in rye straw loaded in freight containers in large-scale tests. Copper plate corrosion values indicating the severity of exposure to hydrogen phosphide were 13 and 12, and mean temperatures of five locations in the freight container were 25 and 26 degrees C in large-scale tests with the larvae and adults, respectively. Hydrogen phosphide concentrations were > or = 400 ppm throughout the 3-d fumigation for larvae and during the first day of fumigation for adults. We propose that cereal leaf beetle can be controlled by a single treatment of bale compression followed by a 1-d storage period or by a fumigation in which 400 ppm hydrogen phosphide is maintained for 1 d at 21 degrees C or above. We confirmed that a multiple quarantine treatment of bale compression) followed by a 3-d fumigation will control cereal leafbeetle in exported rye straw.

Quarantine Control of Hessian Fly (Diptera: Cecidomyiidae) in Exported Hay: A New Treatment for Large-Size, Polypropylene Fabric-Wrapped Bales and a 3-d Fumigation for Compressed Standard Bales

“…Procedures used were similar to those described by Yokoyama et al (1996Yokoyama et al ( , 1999 for standard-size hay bales and modiÞed for use with large-size bales. A large-scale commercial test of a 3-d hydrogen phosphide fumigation for compressed standard bales was conducted on 26 Ð29 July 2000 in Aurora, OR, using procedures described by Yokoyama and Miller (2002).…”

“…The large-scale commercial test of the 3-d hydrogen phosphide fumigation of Hessian ßy puparia in compressed standard bales was conducted simultaneously with a large-scale commercial test with cereal leaf beetle, Oulema melanopus (L.), adults as described by Yokoyama and Miller (2002). One of Þve compressed standard bales containing three bags of infested wheat seedlings was placed in each of the following positions in a freight container: front top, front bottom, middle bale, back top, and back bottom.…”

“…The freight containers were loaded with 26 rows (16 bales per row), and rows 1, 13, and 26 were considered the front, middle, and back (adjacent to the door), respectively. Temperatures and fumigant concentrations were determined as previously described (Yokoyama and Miller 2002). The freight container was fumigated for 3 d with 60 g aluminum phosphide/28.3 m 3 .…”

“…An increase in bale pressure was related to an increase in mortality of Hessian ßy puparia (Yokoyama et al 1993a, b) and would help control the test population. This pressure (105 kg/cm 2 ) alone resulted in complete control of cereal leaf beetle larvae (Yokoyama and Miller 2002).…”

“…The large-scale commercial test of the 3-d fumigation to control Hessian ßy in compressed standard bales was conducted under the same conditions as those reported for cereal leaf beetle adults (Yokoyama and Miller 2002). The sum of the copper plate corrosion values from each of six locations in the freight container after a 3-d fumigation was 12, indicating that the fumigant penetrated the compressed bales that contained Hessian ßy puparia.…”