RESEARCH
On-Farm Grain Storage Facilities and Management
Practices in Kentucky
ROBERT]. BARNEY, DAVID
Wesent a questionnaire to growers
in west and central Kentuckywho store grain on
their farm to determine the extent of their stor·
age facilitiesand managementpractices.The following topics are presented: profile of respondents, storage facilities,duration of storage, bin·
fillingstrategy;on-farmfeeding of grain, inspection procedures, applicationof insecticides,pest
problems,and sources of information.
ABSTRACT
O
N-FARMCAPACITYfor grain storage has increased steadily in the
United States since the early 1970s
(Storey et al. 1983). However, few surveys of
stored-grain pests have been conducted.
Published work from Michigan (Ruppel
1977), Nebraska (Spitze 1980), Minnesota
(Barak & Harein 1981), South Carolina
(Horton 1982), and a survey sponsored by
the Agricultural Stabilization and Conservation Service (ASCS) of 27 states (Storey et
al. 1983) have revealed that insects, mites,
and molds are serious problems of stored
grain.
Before conducting a sampling survey of
on-farm storage structures in Kentucky, we
decided to prepare a questionnaire to survey farmers who store grain on their farms
about their storage facilities, management
practices, and willingness to participate in
the subsequent sampling survey. The objective of our study was to collect information
on current on-farm grain storage facilities
and management practices in Kentucky with
a questionnaire, which, when coupled with
a subsequent sampling survey, will provide
a more complete description of the storedgrain situation in Kentucky and provide insights into improving the on-farm management program currently in place (Raney
1984).
Materials and Methods
Mailing. The Commonwealth of Kentucky
is divided into six crop reporting districts.
According to the Kentucky Agricultural Statistics Service (1986), acreages of corn, soybean, and wheat are heavily concentrated in
the three westernmost districts; (1) Purchase Region, 11 counties; (2) Midwestern
26
E. LEGG, AND JOHN D. SEDLACEK
Region, 15 counties; and (3) Central Kentucky Region, 24 counties. Because these
are the crops most likely to be placed in onfarm storage in Kentucky, the questionnaire
was only used in these three districts.
The mail survey in this study was conducted according to methods described by
Dillman (1978) with several modifications.
Six county agriculture extension agents
were chosen randomly from each of the
three districts and asked to provide a list of
growers who were known to store grain on
their farms (only five agents responded
from District 3). A total of 1,322 names from
17 counties was provided and questionnaires were mailed to this group in self-addressed stamped envelopes. 1\vo weeks
after the initial mailing a reminder letter
was sent to those who had not responded.
Two weeks later a second questionnaire
was sent to those who had still not responded.
ValiditYStudy. A major assumption of any
surveyor questionnaire is that the respondents represent a valid cross section of the
population being surveyed. To test this assumption, a validity study was performed
using census figures from the Kentucky Agricultural Statistics Service (1986) to compare data gathered from the questionnaire
and census data.
Two regressions were used to analyze the
census data: (1) acres of corn, soybean, and
wheat harvested versus total acres of cropland harvested and (2) yield of corn, soybean, and wheat versus total acres of cropland harvested. Both regressions were very
significant (b ± SE = 1.112 ± 0.072, r =
0.941 and b ± SE = 70.913 ± 5.492, r =
0.917, respectively), indicating that corn,
soybean, and wheat represented the vast
majority of harvested crops in these districts in 1985.
Three regressions were used to analyze
questionnaire (Q) and census (C) data: (1)
Q acres farmed versus C acres harvested,
(2) Q acres farmed versus C acres of corn,
soybean, and wheat planted, and (3) Q yield
versus C yield of corn, soybean, and wheat.
These regressions revealed similar, though
not as strong, relationships
(b ± SE =
0.302 ± 0.058, r = 0.647; b ± SE = 0.261
± 0.051, r2 = 0.637; b ± SE = 0.167 ±
0.033, r = 0.625; respectively). These results indicate that trends reflected in the
census data were also reflected in the questionnaire; therefore, data from the questionnaire should be representative of central and western Kentucky growers.
Kentucky was one of 12 case studies in
the National Evaluation of Extension's Integrated Pest Management (IPM) Programs
(Rajone et al. 1987). The participants, 100
growers from eight counties in central and
western Kentucky, were characterized and
compared on the basis of their level of IPM
use. Although the purposes of our questionnaire and the above-mentioned survey differed, the areas of overlap are examined
and discussed in the Results and Discussion.
Survey Questionnaire.
Our questionnaire consisted of a cover letter and four
pages containing 20 questions arranged in
five general categories, with space on the
last page for comments, suggestions, and an
invitation to participate in the statewide
sampling survey as a follow up to the questionnaire. The five general areas were (1)
storage facilities and grain use, (2) storage
inspection procedures, (3) pesticide use,
(4) information sources, and (5) personal
information.
Data Analysis. Data were analyzed using
the maximum likelihood ratio or Pearson's
X2 test for heterogeneity (Nimis & Heisey
1985). Comparisons were made between
districts and among possible responses for
each question by examining observed and
expected responses. Log-linear models
were used to fit the data when analyzing a
multidimensional contingency table (Nimis
& Heisey 1985).
ROBERT J. BARNEY and JOHN D. SEDLACEK are research entomologists in the Plant and Soil Science Program of the Community Research Serl'ice, Kentucky State Universif)\ Frankfort. DAVin
E. LEGG is currently in the Department of Plant,
Soil and Inseet Sciences, University of Wyoming,
Laramie. Wvo. 82071.
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Results and Discussion
Profile of Respondents. Questionnaires
were returned from 717 or 54.2% of the
mailings. However, only 401 or 30.3% of the
questionnaires were returned and completed by farmers who currently store grain
on their farms. Our discussion is based on
these 401 respondents. It must be remembered that each question was not answered
by all respondents.
Almost three quarters (74.9%) of the respondents consider themselves full-time
farmers. The remainder (13.6%) either derive most of their income from farming or
farm on a very limited basis (11.5%). There
was no district influence (X2 = 0.8, df = 4,
P = 0.9333).
The majority (75.9%) of the farmers were
distributed evenly among the following
three age groups: 33-42, 43-52, or 53-62
years. The average age of the respondents
was 48 years. The average number of years
farming was 28.2. However, years of experience ranged from 1 to 75, and many respondents wrote in "life." There was no district influence on age (X2 = 17.8,df = 10, P
= 0.0575) or experience (X2 = 26.9, df =
28, P = 0.5196).
The vast majority of respondents had a
high school education (86.0%), and 23.5%
possessed a college degree. There was no
district influence (X2 = 12.7,df = 10, P =
0.2403).
The majority of the respondents farm less
than 1,500 acres (86.6%) with 43.4% farming less than 500 acres. However, a significantly greater proportion of farms in District 3 were in the range of 1-499 acres
(55.2%), while Districts 1 and 2 reported
only 32.5 and 39.3%, respectively, in this
size category (X2 = 40.8, df = 16, P =
0.0006). Rajotte et al. (1987) also found that
41% of the respondents farmed less than
500 acres.
Storage Facilities. The first question in
this category was designed to determine
on-farm storage capacity and the number
and type of storage structures that are used.
Growers were asked to list the number of
storage structures on their farm by capacity
in bushels, e.g., two bins at 5,000 bu, one
bin at 12,000 bu, and one bin at 30,000 bu.
This represents a complete breakdown of
their storage facilities. However, many respondents only provided total number of
bins and a capacity without providing a binby-bin breakdown, e.g., four bins-52,000
bu. In these instances we had to decide if
the actual situation was four bins with a
combined capacity of 52,000 bu or four
bins of 52,000 bu each for a total capacity of
208,000 bu. These decisions were simplified by data provided in a following question that dealt with a breakdown of comWINTER 1989
modity by bushel. If the follow-up question
indicated that 49,000 bu of corn was stored,
then 52,000-bu total capacity was selected.
We then assumed that each bin capacity was
13,000 bu.
Total on-farm storage capacity in steel
bins was calculated by multiplying the number of bins by their capacity and summing
the values. Reported capacities ranged from
375 to 240,000 bu per farm. Farms were divided into seven size classes using increments of 15,000 bu with the largest class
being 2:90,000 bu. Most farms were in the
two lowest capacity classes (39.0 and 24.8%,
respectively) (Fig. 1). District 3 had a disproportionately greater number of farms in
the 0-14,999-bu range (55.6%) (X2 = 27.3,
df = 12, P = 0.0070). Rajotte et al. (1987)
also found a wide range of storage capacities (35-200,000 bu), with an average of
28,711 bu per farm.
Individual bin capacities were grouped
into six size classes using increments of
5,000 bu with the largest class being
2:25,000 bu. Most bins were in the two lowest capacity classes (39.6 and 36.9%) (Fig.
2). There was no district influence on bin
size (X2 = 13.3, df = 10, P = 0.2063). The
average number of bins per farm was 4.0.
A small percentage
of respondents
(14.9%) indicated that they also use cribs
for storing corn (unshelled). The majority
of the cribs (52.7%) were located in District
3. One half (53.6%) of the cribs were estimated to hold >2,000 bu. There was a
greater number of 1,000-1,500 bu cribs in
District 3 than expected (X2 = 22.0, df = 8,
P = 0.0048). Crib storage must be considered a minor method of on-farm grain storage in Kentucky as compared with galvanized steel bins.
Duration of Storage. Almost all respondents (93.4%) store corn on their farm.
Most of those farmers (62.9%) store less
than 20,000 bu of corn (Fig. 3). There was
no district influence (X2 = 28.9, df = 28, P
= 0.4171).
There were two distinct peaks in duration of corn storage (Fig. 4). The initial
peak, which represented 77.5% of the respondents, was corn stored less than one
year. The second peak was corn stored between 2.5 and 3 years. This bimodal distribution demonstrates two storage strategies:
(1) short-term storage until feeding out or
sale and (2) long-term storage due to participation in governmental grain reserve
programs. There was no district influence
(x2 = 13.7,df = 10,P = 0.1866).
Rajotte et al. (1987) did not report a bimodal distribution in duration of corn storage. All respondents in their survey stored
their corn on-farm for 12 months or less.
Less than one-half (42.5%) of the respondents store soybeans on their farm. Of
those that do store soybeans, 70.0% store
less than 10,000 bu (Fig. 3). In District 3 significantly more respondents than expected
did not store soybeans and those that did
store soybeans stored smaller quantities
(X2 = 74.2, df = 20, P = 0.0001).
Duration of storage for soybeans followed the same bimodal pattern as corn
(Fig. 4). The first peak represented 82.7%
Percent of Farms
60
50
_
District
1
_
District
2
_
District
3
40
30
20
10
o
0-15
15-30
30-45
45-60
60-75
75-90
90>
Farm Storage Capacity (1,000 bu)
Fig. 1. Total on-farm grain storage capacity in steel bins by crop reporting district in
Kentucky.
27
Percent of Bins
60
_
50
District
1
_
District
2
_
District
3
40
30
20
10
o
0-5
5-10
10-15
15-20
Bin Capacity
20-25
25>
(1,000 bu)
Fig. 2. Distribution of steel grain bins IYy storage capacity in crop reporting districts in
Kentucky.
Percent of Farms
180
160
140
_
corn
_
soybean
_
wheat
80
60
90>
On-Farm Storage (1,000 bu)
Onfarm storage of corn, soybean, and wbeat in Kentucky.
19.0, df = 12, P = 0.0882).
Duration of storage for wheat followed
the same bimodal pattern as corn and soybeans (Fig. 4). The first peak represented
814% and the second 11.7% of the respon28
24.7, df
=
4, P = 0.0001).
0.6073).
The next question in this category concerned who inspects the storage bins. The
overwhelming majority of farmers inspect
their own bins (88.7%), an additional 3.6%
use a helper. There was no district influence
(X'
and the second 12.8% of the respondents.
There was no district influence (X' = 14.1,
df = 10, P = 0.1645).
Only 37.5% of the respondents
store
wheat on their farms. Of those that do store
wheat, 81.1% store less than 10,000 bu (Fig.
3). There was no district influence (X' =
=
No respondents indicated that they feed
any stored soybeans to their livestock.
Inspection Procedures. The question
was posed, "What four factors do you think
are the most important in maintaining
stored grain quality?" The top four factors
were moisture content (25.9%), temperature (21.8%), insect control (19.9%), and
storage time (11.5%). Other factors considered less important were molds (8.9%),
sanitation (5.4%), dockage (4.2%), rats
(2.1), and diseases (0.3%). There were no
district influences (X' = 13.8, df = 16, P =
100
Fig. 3.
number of farmers in Districts 1 and 2 feed
at least three-quarters of their corn to livestock (X' = 42.5, df = 4, P = 0.0001).
Only 410% of the farmers that responded
to the question pertaining to the feeding of
stored corn to livestock responded to the
same question concerning wheat. In addition, 77.5% of the farmers that did respond
indicated that they fed less than 25%. As
was seen for corn, a greater-than-expected
number of farmers in District 3 feed at least
three-quarters of their wheat to livestock
(X'
120
0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90
beans usually have few insect problems.
More than two-thirds (67.6%) of the respondents indicated that they do not follow
a panicular strategy. Another 30.0% indicated that they try to refill a bin with the
same kind of grain. There was no district
influence (X' = 2.1, df = 4, P = 0.7166).
On -Farm Feeding of Grain. Farmers were
asked what percentage of on-farm stored
grain was eventually fed to livestock on
their farms. More than one-half of the respondents (56.3%) indicated that they feed
less than 25% of their stored corn to their
livestock. However, 31.7% of the respondents did indicate that they feed 76-100% of
their stored corn to livestock. A greaterthan-expected number of farmers in District 3 feed at least three-quarters of their
corn to livestock. A lesser-than-expected
dents. There was no district influence (X' =
6.1, df = 8, P = 0.6356).
Bin-Filling Strategy. We wanted to determine if farmers followed a grain rotation
strategy. In other words, do they make a
conscious effort to refill a bin with the same
kind of grain or to refill a bin with a different kind of grain, or they do not follow a
particular rotation strategy. Rotation of
grain type within a bin between corn and
soybean may serve the same purpose as rotating these crops in the field. Stored soy-
=
11.5, df
=
8, P
=
0.1745).
The frequency of inspection ranged from
55.4% who inspected 6-10 times a year to
7.8% who did not inspect their grain at all.
An additional 27.2% made 3-5 inspections
per year. Several respondents wrote in that
they inspect their bins every week or two.
There was no district influence (X' = 12.4,
df = 6, P = 0.0521).
Only 14% of the respondent's bins are
inspected by scouts. When the frequency of
inspection was compared with who inspects the bins, we found that bins inspected by scouts were usually only inBULLETIN OF THE ESA
spected 1-2 times a year, while farmers
usually checked their bins >6 times a year
(X' = 51.5,df = 12, P = 0.0001).
The next crucial question was "What
measurements
or observations do you
make when inspecting your stored grain?"
Seven methods and "Other" were provided
as choices with the request to circle all appropriate methods. Only growers who indicated that they inspect their grain were included in the following discussion (n =
368).
Irrespective of inspection methods used,
more than 90% of the farmers used a combination of techniques with 52.9% of the
farmers using three or four methods at each
inspection. There was no district influence
(X' = 4.1,df = 10,P = 0.9419).
In terms of overall usage, testing grain
moisture (82.9%), smelling for odors
(76.4%), and checking grain temperature
(61.1%)were the most frequently used techniques by farmers that inspect their grain.
Checking the grain surface (46.5%) and using a grain probe (41.3%) also were used
frequently.
When only one method was used, probe
or moisture samples were the most popular
(Fig. 5). When two methods were used,
moisture was tested in combination with
one of the following: smelling for odors,
temperature, or probe samples.
The three-method
combination used
most frequently was moisture, odors, and
Percent
of Farms
200
150
_
Corn
_
Soybeans
_
Wheat
100
50
o
0-6
7-12
13-18
19-24
25-30
31-36
37-42
43-48
Duration of storage (mos)
Fig. 4. Duration of on{arm storage of com, soybean, and wheat in Kentucky.
Percent
of Farms
60
50
_
Moisture
_
Smell Odors
Gill]
Temperature
_
Surface
D
Probe
_
Outside
Bin
40
temperature (Fig. 5). These three methods
remained the most popular in higher inspection combinations (4-6) with additional methods being added to the basic
three.
Several management options are available to a grower when problems are detected. Growers were asked to designate
how frequently they used each of the following options: aeration, fumigation, insecticide, and sanitation. Aeration was the most
frequently used technique as 64.5% of the
respondents indicated that they aerated
their bins five or more times a year during
the past three years (Table 1). The remaining methods were used with similar frequency to each other. There was no district
influence on any of the four above mentioned methods (X' = 7.7, df = 8, P =
0.4538, X' = 10.7,df = 8, P = 0.2146, X' =
8.3, df = 8, P = 0.4031, X' = 5.7,df = 8, P
= 0.6765, respectively).
Application of Insecticides.
The first
question in this category was "How do you
decide when action (fumigation, aeration,
etc.) is needed to prevent grain spoilage or
loss?" The majority of farmers (79.7%) replied that they personally inspect their bins,
rather than rely on neighbors, the calendar,
pesticide dealers, or county agents to make
management decisions. An additional 8.8%
WINTER 1989
30
2
3
4
5
Method Combinations
Fig. 5. Frequency of use of on {arm stored grain inspection methods in Kentuckyalone and in multiple method combinations.
use personal inspection in combination
with one of the previously mentioned
sources of information. There was no district influence (X2 = 13.2, df = 10, P =
0.2088).
A few respondents used a category called
"Other" and indicated that they rely on
drastic changes in the weather as an indicator to aerate their bins. Several respondents
indicated that they monitor grain quality
during periodic feeding of their livestock.
The next question was "Name all the insecticides/fumigants which were used on
each of the stored grains on your farm during the last 3 years and the frequency of
their use." The majority of farmers (61.0%)
indicated that they use some pesticides on
their stored grain. An analysis of pesticide
use by commodity revealed that malathion
is the primary pesticide used in stored
grains in Kentucky (Fig. 6).
More than 60% of the farmers who used
pesticides on their stored corn used malathion. Of those farmers, 59.0% made one
application of malathion per year, and the
remainder made multiple applications. Mul29
'Thblc 1. Frequency of use of several stored grain management techniques in Kentucky
No. times used per year
Technique
Aeration
Sanitation
Insecticide
Fumigation
Other
1t'
262
208
261
229
52
• Numberof respondents.
~5
4-3
2
64.5
3.8
3.4
1.3
0
10.7
6.3
5.4
4.4
1.9
4.6
13.9
18.8
15.3
0
tiple applications per year of malathion
were made more frequently than expected
on corn stored for >18 months (X2 = 38.0,
df = 8, P = 0.0001). There was no district
influence on malathion use on corn (X' =
16.0,df = 10,P = 0.0976).
Methyl bromide, Phostoxin (aluminum
phosphide, Degesch America, Weyers Cave,
Va.), and Actellic (pirimiphos-methyl, ICI
Agricultural Products, Wilmington, Del.)
were used much less frequently on corn
than malathion. In the "Other" category,
Fumitoxin (aluminum phosphide, Pesticon
Systems, Des Moines, Iowa) and carbon tetrachloride were mentioned by two farmers.
At least 15 other pesticides were mentioned
as having been used as stored grain treatments induding chlordane, carbaryl, diazinon, dichlorvos, and atrazine (a herbicide).
Although vinyl strips containing dichlorvos
can be suspended above the grain surface,
chlordane, carbaryl, diazinon, and atrazine
are not labeled for stored grain use.
Approximately 30% of the pesticide users
applied malathion to stored wheat. Multiple
applications per year were only made 27.8%
of the time. Methyl bromide was only used
by a few farmers on stored wheat.
Stored soybeans rarely received a pesticide application. However, when applications were made, malathion was used exclusively. It should be noted that malathion is
not labeled for use on stored soybeans.
1\\'0 additional crops that were reported
as being stored were milo and barley. Each
grain was reported by two farmers.
The vast majority of farmers (82.5%) applied pesticides themselves to their grain,
rather than hiring a helper (7.3%) or a custom applicator (2.0%). A greater-than-expected number of farmers in District 3
hired helpers to apply pesticides (X' =
15.5, df = 8, P = 0.0500). When asked
"How were the pesticides applied?", 428 responses were given. The most frequently
used method (44.2%) was applying insecticide to the empty bin before storage. Application into the auger stream (21.0%) and as
a fumigant during storage also were frequently used techniques. Only 11.7%used a
surface dressing after loading or "Other"
(2.3%). There was no district influence associated with any method.
30
Never
2.3
40.4
44.4
32.3
1.9
17.9
35.6
28.0
46.7
96.2
Pest Problems. Farmers were gIven a selection of eight pests and asked to designate
for each its status as a problem on their
farms. As can be seen in Table 2, not all respondents answered for each pest. However, weevils (rice, granary, and maize)
were designated by the most respondents
and in a most positive manner (66.3% YES)
as the most important pest.
Molds were designated as the second
most prevalent problem (36.0% YES), but
an even greater percentage of farmers
(44.5% NO) did not believe that molds are a
problem in their stored grains. There was
no district influence (X' = 8.2, df = 4, P =
0.0818).
Corn rootworm was inserted into the list
as a nonpest check and only 3.9% believed
that it is a pest of stored grain. However,
26.8% indicated that they were not sure if it
is a pest or not. There was no district influence (X' = 5.4, df = 4, P = 0.2448).
There were several district influences
pertaining to pest problems. The NO response to weevils was found more frequently than expected in District 2 and less
frequently in District 3 (X' = 15.5, df = 4,
P = 0.0037). The YES response to aflatoxin
was greater than expected in District 1,
whereas the NOT SURE response to aflatoxin was greater than expected in District
3 (X' = 17.2,df = 4, P = 0.0018).
Only six respondents used the "Other"
category. The write-in pests were rats and
mice (three), corn weevil (two), and bugs
(one).
We hypothesized that pest problems may
intensify as the duration of corn storage increases. Pests were perceived as an increasing problem up to 18 months (Fig. 7), but
then were believed to be less of a problem
through long-term storage (X' = 26.9, df =
6, P = 0.0001). It must be emphasized that
these are perceived pest problems, which
are not necessarily supported by accurate
inspections or identifications.
The respondents to the IPM questionnaire (Rajotte et a1. 1987) perceived pests as
much more of a problem than did our respondents. Granary weevils (82.4%), storage molds (77.0%), and aflatoxin (63.9%)
were reported as major pests by respondents in the IPM-oriented survey.
Sources of Information. Many sources of
information are available to farmers concerning on-farm grain storage. We were interested to learn what sources are most
highly valued by farmers. Nine sources plus
"Other" were provided on the questionnaire with the instructions to indicate the
"three most valuable." This does not necessarily equate with most frequently used .
County agriculture agents were the most
frequently designated source of information
(67.4%). However, they were used less frequently than expected in District 1 (X' =
43.6, df = 18, P = 0.0006). Farm supply
dealers (45.3%), agriculture magazines
(43.2%), and extension
publications
(42.1%) were the next most valuable
sources of information.
The "Other" category was selected by 32
respondents (10.3%). More than one-half
(56.2%) of them wrote-in "experience" or
"common sense" as one of their most valuable sources of information. This was especially true in District 1. Almost one-third
(31.2%) of the responses indicated an individual associated with their local grain elevator-owner,
operator, grain buyer, or
dealer. We hypothesized that farmers who
seek professional advice may be more inclined to inspect their bins more frequently
than less informed growers. However, a
comparison of frequency of inspection and
sources of information revealed no significant interactions (X' = 15.2, df = 27, P =
0.9669).
Comments. The bottom half of the last
page of the questionnaire was a blank area
where farmers were asked to make comments concerning grain storage and to
write their name, address, and phone number if they were interested in having their
grain inspected as part of the statewide
sampling survey.
The comments expressed were divided
into three categories: requests, comments,
and complaints. Examples of requests are,
"What is cheapest and best pesticide to use
over the top?" or "I need standardized
charts showing moisture and temperature
needed to control insects and condensation." Comments took the form of, "I am
more interested in getting a fair price," ''I'm
never sure when to aerate," and "I think
most grain storage problems come from neglect." Several farmers complained that they
were docked excessively when selling grain
and one person wrote, "It is very unfair to
the individual farmer who earnestly tries
and does a good job of producing, storing,
and maintaining quality grain to then have
it blended with inferior grain for export by
the shipping elevators."
District Influence. Responses from District 3, the Central Kentucky Crop Reporting
District, were significantly different from
BUlLETIN OF THE ESA
Table 2.
Respondents perception of pest problems in on-farm stored grain in Kentucky
Pest Is a problem? (II>)
P~st
Weevils·
Molds
lndianmeal moth
Flour beetle
Angoumois grain moth
Aflatoxin
Other
Corn rootworm
Grain rust
n"
Yes
No
Not Sure
335
256
270
254
264
245
104
231
233
66.3
36.0
24.1
23.6
16.3
13.5
9.6
3.9
3.0
20.3
44.5
34.4
38.2
37.5
62.4
55.8
69.3
66.5
13.4
19.5
41.5
38.2
46.2
24.1
34.6
26.8
30.5
• Number of respondents.
b Rice, granary, or maize weevils.
Percent
of Farms
35
_
corn
_
wheal
_
soybean
15
5
o
total acres harvested.
phostox in
Insecticide
Fig. 6.
Treatment
Useof pesticides on onfarm stored corn, wheat, and soybean in Kentucky.
Percent
of Farms
70
60
_
YES PESTS
_
NO PESTS
_
NOT SURE
50
40
30
20
10
o
0-6
6-12
12-18
18-24
24-30
30-36
Duration of Storage (mas)
Fig. 7. Farmer's perceptions of pest problems in onjarm stored corn in Kentucky relatzve
to storage time.
WINTER 1989
the other two districts in the following instances:
• greater percentage of small farms (0-499
acres)
• greater percentage of low storage capacity farms «15,000 bu)
• greater percentage of corn cribs (1,0001,500bu)
• lower percentage of farms storing soybeans
• greater percentage of farms feeding corn
to livestock
• greater percentage of farms feeding
wheat to livestock
• greater percentage of farms reporting
weevil problems
• greater percentage of farms hiring helpers to apply pesticide
Farms in District 3 can be characterized
as being smaller and more diversified than
farms in the westernmost part of the Commonwealth. Also, these farms maintain
more livestock, thus requiring more onfarm feeding.
It is difficult to hypothesize as to why a
greater percentage of farms in District 3 reported pest problems with weevils in their
stored grain. Until we conduct the sampling
survey we will not know if these are real or
perceived problems.
Summary. The validity study showed that
similar relationships existed with census
and questionnaire data concerning acreage
and yield of corn, soybean and wheat and
This indicates that the
respondents were a representative sample
of farmers storing these grains on-farm
within these crop reporting districts.
We created a profile or composite of the
average respondent who stores grain onfarm in Kentucky in Districts 1-3 (see sidebar). This information serves as a summary
of a hypothetical on-farm storage situation.
The more noteworthy items are that most
grain is stored in one of two possible situations: for less than one year or held for the
long term. Many farmers commented that
they encountered few or no pest problems
in grain stored for less than one year because it is stored only during fall, winter,
and spring and then fed or sold before pest
problems can develop.
Most of the management (inspecting and
treating) is done by the farmer. Only weevils were considered to be a major problem
in stored grain. However, the identity of the
reported stored-grain pests has not been
confirmed by an entomologist, and it is
highly probable that any beetles found were
considered weevils. It should be noted that
the farmers consider county agriculture extension agents as their most reliable source
of information.
Results of this survey will be compared
with results of the subsequent on-farm
31
Profile of the average
Kentucky
sampling
survey. Information
from this
questionnaire
and the future survey will be
used to assist extension specialists, county
agents, and growers make more informed
decisions
concerning
stored-grain
pest
management.
•
farmer that stores grain on-farm
Profile of Respondents
Education: high school
Age: 48 years
Acreage: 827 acres
Farming: 28 years, fulltime
Storage Facilities
Total farm storage capacity: 31,735 bu
Mean number of bins: 4-3 0-10,000 bu & 1 >10,000 bu
Duration of Storage
<20,000 bu, <1 yr or 2.5-3 years
Corn storage:
<10,000 bu, <1 yr or 2.5-3 years
Soybean storage:
<10,000 bu, <1 yr or 2.5-3 years
Wheat storage:
Bin-Filling Strategy
Do not follow a particular rotation strategy
On-Farm Feeding of Grain
<25 % of corn fed to livestock
Inspection Procedures
Who inspects: inspect themselves
Frequency: 6-10 inspections or more per year
Method: test grain moisture, temperature, smell for odors
Acknowledgment
We thank Scott Frey and Nora Harberson for
help in the mailing and processing of the ques·
tionnaire and Harley Raney, University of Kentucky, for providing the mailing list. This investigation was supported
in part by a USDA,
Cooperative State Research Service gram to Kentucky State University under agreemem KYX-1087-06P.
References
Cited
Most Common Management Technique
Barak, A. V. & P. K. Harein.
Aeration
Application of Insecticides
When to apply: Rely on personal inspection
What is applied: Corn-malathion
(60%)
Wheat-malathion
(30%)
Soybeans-malathion
(12%)
Who applied: Farmers did it themselves
How applied: To empty bin before storage
Pest Problems
Weevils: rice, granary, and maize
Most Valuable Sources of Information
Farm supply dsalers
County extension agents
Extension publications
Agriculture magazines
tion of farm- stored shelled corn and wheat in
Minnesota. J. Econ. Emomo!. 74: 197-202.
Dillman, D. A. 1978. Mail and telephone surveys:
the total design method. Wiley,New York.
Horton, P. M. 1982. Stored product insects collected from on-farm storage in South Carolina.
J. Ga. Emomo!. Soc. 17:485-491.
Kentucky Agricultural Statistics Service. 1986.
Kemucky agricultural statistics 1985-1986.
Louisvil.le. 136 pp.
1988. Kentucky Agricultural Statistics 19871988. Louisville. 143 pp.
Nimis, G. & D. Heisey. 1985. Statistix. NH Analytical Software, St. Paul, Minn.
1981. Insect
infesta-
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BULLETINOF THE ESA
RaJotte,E. G., R. E Kazmierczak,G. W. Norton,
M.T.Lambur & w. A.Allen. 1981. The National
evaluationof Extension'sintegrated pest management (IPM) programs. Appendix 10: Kentucky stored grain IPMimpact study.Virginia
Cooperative Extension Service Publication
491-021. Blacksburg.
Raney,H. G. [ed.]. 1984. Managementof on-farm
stored grain. Collegeof Agriculture,Cooperative ExtensionService,Universityof Kentucky,
Lexington.
Ruppel, R. F. 1977. An inventoryof stored grain
insects in Michigan.Great LakesEntomol.10:
243-244.
Spitze, D. C. 1980. Farm-stored grain survey.
WadeCountyFarm,Research,and HomeQuarterly.Universityof Nebraska,Lincoln.Fall 1980:
16-17.
Storey,C. L., D. B. Sauer & D. Walker. 1983. Insect populations in wheat, corn, and oats
slOredon the farm.J. Econ.Entomol.76: 13231330.
Receil'ed for publication
cepted 10 April 1989.
9 january
1988; ac-
RESEARCH
Quality Control in Insect Mass Production:
A Review and Model
N. C.
LEPPlA AND
ABSTRACTMassproductionof insectsrequires
a pervasive quality control system that extends
from initialplanningthrough fieldevaluationand
feedbackto all manageriallevels.The current developmentof insect colonization,strain maintenance, and quality control principles is discussed, followed by a model for Lepidoptera
based on the fall armyworm, Spodoptera frugiperda Q. E. Smith). Finally, an organizational
structure is proposed for interfacing the functions of methods development,production,product use, and specialized qualitycontrol.
UALI1YCONTROL of mass-produced insects currently includes
a number of interrelated but not
yet unified concepts. The immediate challenge is to define procedures and
develop operational principles. Moreover,
species-specific standards and specifications are needed before tests and equipment can be designed for efficient monitoring of required insect characteristics.
Although some form of quality control technology already exists as an integral component of most insect mass-rearing programs
(Fig. 1), the complex production processes
must be monitored and controlled with sophistication to ensure reasonably consistent
product quality. The reliability of these
quality control determinations depends on
existing rearing capabilities, and the precision with which insect strains are colonized
and maintained. Eventually,by means of systematic process and product quality control, production and use will be optimized.
Associated data acquisition and analysis will
be incorporated into feedback networks
that transmit information directly to appropriate organizational levels, making it possible for management to orchestrate the decision-making process.
Q
"A major book that will be used
regularly by a large number of entomologists and environmental scientists. "-Charles
L. Remington
Eradication
of Exotic Pests
Analysis with Case Histories
edited by Donald L. Dahlsten
and Richard Garcia; Hilary
Lorraine, associate editor
In this book, experts in pest control
discuss the most recent methods for
and implications of eradicating exotic
pests and make recommendations for
developing methods of biological
control. 23 illus. $ 3S .00
Yale University Press
Dept. '7', 92AYale Station
New Haven, CT 06 po
WINTER1989
Insect Colonization
The process of colonization consists of
defining a specific purpose for the insects,
prescribing associated specifications, developing a dependable rearing capability, collecting samples suitable for strain development, and establishing
the colony. In
autocidal (sterile insect technique and genetic manipulation) and other biologically
T R. AsHLEY
based control programs, the ultimate purpose is to reduce the density of the target
population to a level that virtually eliminates economic damage or the incidence of
disease. To achieve this purpose, insect
quality is specified according to standards
for performance in the field and is linked
with the characterization of the target population and candidate strain. This characterization often includes some estimate of habitat preference, population density, host
selection, host-finding ability, dispersal, environmental adaptability, longevity, reproductive potential, genetic variability and
other pertinent biosystematic traits.
An effective rearing capability is probably
the most important factor in insect colonization, mass production, and quality control. The major groups that can be mass
reared adequately include certain tephritid
fruit flies, biting flies and other Diptera of
medical and veterinary importance, Lepidoptera, Coleoptera and entomophagous arthropods. Their propagation is necessary
only because sufficient quantities of these
insects cannot be collected in the field,
quarantine regulations preclude release of
field-collected insects, or because they must
be modified during growth and development. Successful mass rearing provides for
required availability, uniformity, economy,
and quality of insects.
Optimization of the rearing system before a new strain is colonized minimizes
the laboratory adaptation required to
achieve acceptable levels of production. Superior rearing techniques and associated
quality control procedures are based on
species-specific behavior, ecology, and demography. For example, constant rearing
conditions may be adequate for some species, whereas a variable environment is better for others. In certain cases, sex ratios
may be skewed by discarding insects that
do not develop within a prescribed period
C. LEPPlA is Director of Methods Development, Science and Technology, USDA-APHIS.
TOM R. AsHLEY codirects APHIS' largest methods
development project at the screwworm mass
rearing facility, 7U.xtlaGutierrez, Chiapas, Mexico. The authors are dedicated to assuring a
sound scientific and technical basis for operational programs in arthropod and weed control.
NORMAN
33