Group Title: Research report - North Florida Research and Education Center ; 90-18
Title: Effects of systemic insecticides on grain yield of hessian fly susceptible and resistant wheat varieties
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Permanent Link: http://ufdc.ufl.edu/UF00066087/00001
 Material Information
Title: Effects of systemic insecticides on grain yield of hessian fly susceptible and resistant wheat varieties
Series Title: Research report (North Florida Research and Education Center (Quincy, Fla.))
Physical Description: 2 p. : ; 28 cm.
Language: English
Creator: Hartman, J. B ( John B. ), 1962-
North Florida Research and Education Center (Quincy, Fla.)
Publisher: North Florida Research and Education Center
Place of Publication: Quincy Fla
Publication Date: 1990
 Subjects
Subject: Hessian flies   ( lcsh )
Wheat -- Effect of pesticides on   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: by J.B. Hartman ... et al.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00066087
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71154208

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North Florida Research and Education Center Research Report NF-90-18
September, 1990


Effects of Systemic Insecticides on Grain Yield
of Hessian Fly Susceptible and Resistant Wheat Varieties
by J.B. Hartman, R.K. Sprenkel, R.D. Barnett, and A.R. Soffes




A fall application of either phorate (Thimet8) or disulfoton (Di-syston) is recommended for
wheat growers who plant susceptible varieties in areas where Hessian fly is known to be a problem.
This at planting application provides approximately six weeks of protection to the young wheat plants
getting them through their most vulnerable stage. However, work done at the University of Georgia
during the 1988/89 season showed that winter and spring infestations could reach damaging levels.1
Flaxseed counts of resistant wheat grown at Marianna in 1989 showed low numbers of flaxseed.

In order to test the desirability of spring applications and applications for the control of low
level infestations, the first year of a 2 year trial was carried out at Marianna. Six varieties were used,
three susceptible and three resistant. Florida 301H is a backcross line of Florida 301 with genetic
resistance to Hessian fly. Florida 301 and 301H are early maturing varieties and are nearly identical
in growth habit and appearance. Similarly, FL85363-G18-14 is a backcross line of Florida 302. They
are both late varieties. Coker 9766 and Florida 303 are unrelated. The susceptible varieties were
given one of four treatments: No insecticide treatment, an application of Thimet(20G at 7 Ib/A) drilled
with the seed at planting, the same application of Thimet plus a spring application of Di-syston (8EC
at 1 pt/A), or Thimet at planting followed by two spring applications of Di-syston. The resistant
varieties were given one of three treatments: no insecticide, at-planting application, or at planting plus
one spring application. The initial (at planting application) was made November 15th, and the side
applications were made FebruayJ1,._ 1990 and March 1, 1990. All treatments were replicated six
times. Central Science

The results showed no positive effect from applying system ic insecticides to resistant cultivars
(Table 1). Insecticide applicati ns had no, effect ip, the reduction of flaxseed on resistant wheats.

A single spring application ha positive effects on both y eld (Table 1) and test weight (Table
2) of susceptible varieties. Yields ofriFo7iddi8o illustrate this effect most dramatically. Flaxseed
counts were reduced from 55 flaxseed/culm for untreaed Flori a 302 to 5 flaxseed/culm for Florida
302 with three applications.

These data suggest that it is probably unprofitable to apply systemic insecticides when using
resistant varieties or under conditions of low Hessian fly pressure. It also suggests that when growing
a susceptible variety in an area heavily infested with the Hessian fly a spring application of Di-syston
may be desirable in addition to the in the row fall granular application.






'Buntin, G. David and Paul Raymer. 1989. Susceptibility of winter wheat and triticale to the Hessian
fly. Georgia Agri. Exp. Sta. Research Bulletin 389.








Table 1. Effects of Multiple Applications of a Systemic Insecticide
on Grain Yield (bu/A) of Susceptible and Resistant Wheat Varieties
Grown in a Field at Marianna, Florida Heavily Infested by the Hessian
Fly (1990).


GRAIN YIELD (bu/A)
UNTREATED FALL TRT. FALL & SPR FALL & 2 SPRING


VARIETY


FLORIDA 301 45.2 d-f# 51.2 b-d


FLORIDA 301H*

FLORIDA 302


49.6 b-e


20.3 h


FL85363-G18-14* 52.1 b-d

FLORIDA 303 40.5 e-g


COKER 9766*


62.0 a


45.2 d-f


35.7 g


48.3 c-f


50.6 b-d


61.8 a


53.5 a-d

50.3 b-d

39.5 fg

47.5 d-f

58.6 ab

58.8 ab


53.3 a-d


40.6 e-g


57.8 a-c


*variety containing genetic source of resistance to the Hessian fly.
#values with the same letter are not significantly different for
Duncan's Multiple Range Test (Alpha = .05) (SAS INST, 1991).


Table 2. Effects of Multiple Applications of a Systemic Insecticide
on Test Weight (lb/bu) of Susceptible and Resistant Wheat Varieties
Grown in a Field at Marianna, Florida Heavily Infested with the
Hessian Fly (1990).


TEST WEIGHT (Ib/bu)
VARIETY UNTREATED FALL TRT. FALL & SPR FALL & 2 SPRING


FLORIDA 301 56.2 b-d# 56.5 a-c 56.5 a-c 56.4 a-d

FLORIDA 301H* 56.6 a-c 56.3 b-d 56.8 ab --

FLORIDA 302 53.9 i 54.8 gh 54.5 hi 55.0 f-h

FL85363-G18-14* 55.9 b-e 55.4 d-g 55.7 c-f --

FLORIDA 303 55.3 e-h 56.7 ab 57.1 a 57.1 a

COKER 9766* 56.6 ab 56.4 a-c 56.4 a-c --


*variety containing genetic source of resistance to the Hessian fly.
#values with the same letter are not significantly different for
Duncan's Multiple Range Test (Alpha = .05) (SAS INST, 1991).




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