October 2021 - 33

RESEARCH
Shipment #1
Mean (± SEM) Number of Eretmocerus eremicus per 10 mm2
(Kansas State University Laboratory)
SUPPLIER*
Supplier A
Supplier B
P-value
NUMBER ON
STICKY CARD
4.2 ± 0.5
10.1 ± 0.5
<0.0001
NUMBER ON
JAR BOTTOM
1.5 ± 0.2
4.4 ± 0.7
0.0034
NUMBER FAILED
TO EMERGE
9.1 ± 0.5
12.5 ± 1.6
0.0706
*Supplier A had a total of 565 (n=5) E. eremicus with a mean total of 113 ± 1.3 per
78.5 mm2
77.2 ± 5.8 per 28.3 mm2
and Supplier B had a total of 386 (n=5) E. eremicus with a mean total of
.
Mean (± SEM) Number of Eretmocerus eremicus per 10 mm2
(Biological Control Distributor)
SUPPLIER*
Supplier A
Supplier B
P-value
NUMBER ON
STICKY CARD
6.0 ± 0.5
19.1 ± 1.3
<0.0001
NUMBER ON
JAR BOTTOM
1.3 ± 0.3
2.8 ± 0.6
0.0510
NUMBER FAILED
TO EMERGE
10.5 ± 0.8v
10.7 ± 0.8
0.8406
*Supplier A had a total of 683 (n=5) E. eremicus with a mean total of 136.6 ± 8.3 per
78.5 mm2
93.2 ± 4.5 per 3.3 mm2
and Supplier B had a total of 466 (n=5) E. eremicus with a mean total of
.
Table 1. Supplier and P-value, shipment number, and mean (± SEM)
number of Eretmocerus eremicus adults per 10 mm2
captured on yellow
sticky cards from release cards received in shipment from two biological
control suppliers. Means within a column followed by a P-value greater
than 0.05 are not significantly different as determined by a Student's
t-test [t(1)=12.70].
Shipment #2
Mean (± SEM) Number of Eretmocerus eremicus per 10 mm2
(Kansas State University Laboratory)
SUPPLIER*
Supplier A
Supplier B
P-value
NUMBER ON STICKY
CARD
14.5 ± 2.0
8.1 ± 0.9
0.0209
NUMBER ON
JAR BOTTOM
1.2 ± 0.1
2.2 ± 0.3
0.0301
NUMBER FAILED
TO EMERGE
6.1 ± 0.2
9.0 ± 0.9
0.0167
*Supplier A had a total of 839 (n=5) E. eremicus with a mean total of 167.8 ± 14.3 per
78.5 mm2
55.2 ± 4.0 per 28.3 mm2
and Supplier B had a total of 276 (n=5) E. eremicus with a mean total of
.
Mean (± SEM) Number of Eretmocerus eremicus per 10 mm2
(Biological Control Distributor)
SUPPLIER*
Supplier A
Supplier B
P-value
NUMBER ON
STICKY CARD
20.9 ± 0.4
8.0 ± 1.2
<0.0001
NUMBER ON
JAR BOTTOM
0.6 ± 0.1
1.1 ± 0.3
0.1998
NUMBER FAILED
TO EMERGE
6.7 ± 0.5
14.0 ± 1.0
0.0002
*Supplier A had a total of 1084 (n=5) E. eremicus with a mean total of 216.8 ± 3.2 per
78.5 mm2
66.0 ± 4.6 per 28.3 mm2
and Supplier B had a total of 330 (n=5) E. eremicus with a mean total of
.
Table 2. Supplier and P-value, shipment number, and mean (± SEM) number of
Eretmocerus eremicus adults per 10 mm2
captured on yellow sticky cards from
release cards received in shipment from two biological control suppliers. Means
within a column followed by a P-value greater than 0.05 are not significantly
different as determined by a Student's t-test [t(1)=12.70].
attached to the inner lid with double-sided tape (Figure 1). The yellow
sticky card section was used to determine the number of E. eremicus
adults that successfully emerged and were functional. The number of
functional adults is the actual number of individuals that can be used
in a biological control program based on their ability to fly and search
for a host. Release cards remained in the Mason jars for two weeks at
77 ± 5° F, 50 to 60% relative humidity under a 16:8 (light:dark) hour
photoperiod on a laboratory bench, with five replications per release
card associated with each supplier (Supplier A and B).
After two weeks, the number of E. eremicus adults captured on the
yellow sticky cards (Figure 2), the number of adults present on the
bottom of the Mason jars, and number of adults that failed to emerge
from the parasitized pupae on the release cards in each Mason jar were
counted. The area the pupae were adhered/glued to on the release cards
differed between Supplier A (78.5 mm2
Therefore, the data were standardized at 10 mm2
) and Supplier B (28.3 mm2
between the two
).
suppliers. Data were analyzed using Microsoft Excel 2016 with significant
mean differences separated using a Student's t-test at α=0.05.
RESULTS AND DISCUSSION
The first shipment from Supplier A had a significantly fewer mean
number of functional adults of E. eremicus captured on the yellow sticky
cards than Supplier B from release cards evaluated at the Kansas State
University Laboratory, as well as from the release cards evaluated by
the biological control distributor (Table 1). There was also a significant
difference between the mean number of adult E. eremicus found on the
bottom of the Mason jars from release cards evaluated at the Kansas
State University Laboratory (Table 1).
Conversely, the second shipment from Supplier B had a significantly
higher mean number of functional adult E. eremicus captured on the
yellow sticky cards than Supplier A from release cards evaluated at
the Kansas State University Laboratory, as well as from release cards
evaluated by the biological control distributor (Table 2). There were also
significant differences between the number of adult E. eremicus found on
the bottom of the Mason jars at the Kansas State University Laboratory
and the number of adult E. eremicus that failed to emerge based on
estimates associated with the release cards evaluated at the Kansas State
University Laboratory and by the biological control distributor (Table 2).
Our preliminary study demonstrates that formulations (release cards)
of biological control agents and emergence of functional adults can
vary depending on shipments from the supplier. Greenhouse producers
typically purchase biological control agents from several commercial
suppliers or distributors. Nonetheless, the logistics associated with
shipping biological control agents is a major issue related to their
quality. In addition, parameters related to quality, including parasitoid
longevity, fecundity, ability to fly and locate hosts, and capacity to
parasitize the target host, cannot be determined until emergence of
adult parasitoids.
Greenhouse producers should conduct a quality assessment similar to
the procedure we have described to ascertain the number of functional
adults that emerge from release cards. This will help assess if the release
cards placed among the crop result in functional adults emerging that
will provide sufficient regulation of the whitefly population. Therefore,
to ensure the success of a biological control program, greenhouse
producers should conduct quality assessments after releasing purchased
biological control agents to determine if they are alive and functional.
There are resources available for greenhouse producers that provide
guidelines on how to conduct quality assessments of commercially
available biological control agents. However, quality assessment requires
a commitment by management and training of employees, which can be
handled through Extension programming.
GREENHOUSE PRODUCT NEWS 33
October 2021

Table of Contents for the Digital Edition of October 2021
