eriococcus lagerstroemiae) crawlers in college station, tx...population dynamics of early stage...
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Population dynamics of early stage Crapemyrtle bark scale (Eriococcus lagerstroemiae) crawlers in College Station, TX
Haijie Dou1, Xiaoya Cai2, Mengmeng Gu2
Texas A&M University, 1College of Agriculture and Life Sciences; 2AgriLife Extension [email protected]; [email protected]
Introduction Crapemyrtle (Lagerstroemia indica and its hybrids) is
valued as a landscape plant for its prolific summer flowers, heat and drought tolerance, and year-round landscape interest, which has been cultivated in the U.S. for over 175 years (Dirr, 1990) and has become one of the plants emblematic of the South. Crapemyrtle bark scale (CMBS), Eriococcus lagerstroemiae (Hemiptera: Eriococcidae), initially discovered in 2004 in north Texas, has rapidly spread throughout Southeastern and Southwestern states (TX, LA, AR, TN, OK, NM, SC, AL, MS and VA), threatening the utility, aesthetics and health of crapemyrtle in urban landscapes.
Thus, determining population dynamics of early stage CMBS crawlers throughout multiple growing seasons is very important to implement management strategies timely and prevent unacceptable levels of CMBS damage.
Results
Conclusion There were probably four peaks of CMBS crawler activity in
College Station, which were around 27th March, 8th May, 26th June and 2nd October, respectively. The largest number of CMBS crawler appeared around 8th May.
The number of crawlers counted from the double-sided sticky tapes each week was significantly different for different locations, trees and branches, which could be caused by natural predators (Fig. 4, Fig 5), different micro-climate (Fig. 6), or previous infestation (no data).
Materials and Methods The number of early stage CMBS crawlers was monitored
weekly using double-sided sticky tape from 6th March to 16th October on twelve crapemyrtle plants at four different locations in College Station, Texas (Fig. 3, Fig. 4).
Three crapemrytle plants were monitored at each location, and five/six double-sided sticky tapes (3 on upper branch, 2/3 on lower branch) each tree.
The average number of CMBS per square inch double-sided sticky tape was counted per weekly.
Figure 7. Average number of CMBS per square inch tape through 6th March to 16th October at locations L1 and L4 (upper and lower branch) in College Station, Texas.
Figure 5. Average number of CMBS per square inch tape through 6th March to 16th October at four different locations in College Station, Texas. The arrows indicate the date of lady beetle present, which are not found at L1 and L2.
Figure 4. Crapemyrtle bark scale (left-up); Pupa of lady beetle, predator of CMBS (left-down) and double-sided sticky tapes placed on crapemyrtle plants (right). Figure 1. The tree on the left was treated with Zylam (dinotefuran)
on 05/28/2014 and there was a difference on the amount of flowers and size with the untreated one (right). The treated plant leafed out earlier than the untreated and had less sooty mold in 2015.
Figure 2. Geographic distribution of confirmed reports of CMBS in the southeastern U.S., November 2014. From http://www.eddmaps.org/cmbs/
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16
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per
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ch L1-Tree1 upper branch
lower branch
Date (2015)
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16
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BS
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ch L1-Tree2 upper branch
lower branch
Date (2015)
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16
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BS
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ch L1-Tree 3 upper branch
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Date (2015)
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16Ave
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L4-Tree1upper branch
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Date (2015)
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16
Ave
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No.
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BS
per
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ch L4-Tree3upper branch
lower branch
Date (2015)
Figure 3. Four different locations where CMBS crawlers were monitored in College Station, Texas.
L4
L3
L1
L2
Summary There were probably four peaks of CMBS crawler activity in
College Station, which were around 27th March, 8th May, 26th June and 2nd October, respectively. The largest number of scale appeared around 8th May (Fig. 5).
The number of CMBS crawlers counted from the sticky tape each week was significantly different for four different locations, three different trees of the same location, and upper and lower branches of the same tree(Fig. 5, Fig. 7).
For the first and second peaks, L1 has the lowest average number of CMBS, but the highest values for the third and forth peaks.
For the first and second peaks, L4 has the highest average number of CMBS, but its value decreased significantly since the present of lady beetle, one of natural predators of CMBS (Fig. 4, Fig 5).
Double-sided sticky tapes
Figure 6. L1 (left, open parking ground) and L4 (right, courtyard), where CMBS crawlers were monitored in College Station, Texas.
Tree 1 Tree 1 Tree 2 Tree 3 Tree 2 Tree 3
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3/6 3/13 3/20 3/27 4/3 4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5 6/12 6/19 6/26 7/3 7/10 7/17 7/24 7/31 8/7 8/14 8/21 8/28 9/4 9/11 9/18 9/25 10/2 10/910/16
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L3 L4
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