Citation
Emergence of overwintering Shuckworm in north florida

Material Information

Title:
Emergence of overwintering Shuckworm in north florida
Creator:
Van Duyn, John.
Publisher:
Big Bend Horticultural Laboratory, Unversity of Florida

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
145599044 ( OCLC )

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7L (4'f--7 BIG BEND HORTICULTURAL LABORATORY
MONTICELLO, FLORIDA
S i i i LSL;Ji r I
Big Bend Hort. Lab. Mime Report BBL 67-7 March 31, 1967

APR 18 ESiGENCE ,OF OVERWINTERING SHUCKWORM IN NORTH FLORIDA

.- by J. W. Van Duyn


Emergence records of the overwintering generation of hickory shuckworm, Laspey-
resoa caryania, were taken in the years 1958, 1959, 1960, and 1966.

Three and one half bushels of infested pecan shucks were placed in each cage.
Infested shucks were collected when they began separating from the nut, but before
the shuck had turned brown. Daily records were taken from each cage when adults of
the shuckworm and parasites began emerging in the next spring.

In 1958 the first emergence was noted on March 13, and peak emergence was
throughout April. About 85% of all moths emerged in April. Emergence in 1959 be-
gan on February 17, and peak emergence was in the second and third week in April,
About 80% of all moths emerged in April. In 1960 emergence was first noted on March
10, and peak emergence occurred during the first three weeks in April. April's
emergence accounted for about 93% of all emergence. Emergence in 1966 began on
March 21, and peak emergence was during the first three weeks in April when about
65% of all moths emerged.

Hymenoptera and diptera parasites were noted to attack shuckworm larva. Para-
sites emerged before the majority of shuckworm moths had emerged. The highest num-
ber of parasites collected was in 1966, when parasites accounted for 24.4% of all
insects emerging. In 1958, 1959, and 1960, the percentage of parasites was 3.3%,
14.7%, and 1.2% respectively. Hymenoptera parasites were generally greater in num-
ber than diptera parasites.

Shuckworm adults emerging in March and April lay eggs on nuts of native hick-
ory. Usually two generations develop in hickory before pecan nuts are large enough
to attack. Second generation adults lay eggs on the side of pecan nuts. Soon
after hatching, the larva penetrates the nut at which time the nut drops. The first
nut drop in 1966 was noted on July 2, 45 days earlier than the recommended spray
dates.

Insecticide tests were conducted using EPN, thiodan, dieldrin, parathion,
malathion, and guthion. EPN and guthion applied three times from August 1, and
two and four weeks later gave good results. All other insecticides tested did not
give satisfactory results. Check plots were very heavily infested.



1Research Associate in Entomology, Big Bend Horticultural Laboratory,
Monticello, Florida.


200 cc










-2-


EMERGENCE OF OVERWINTERING SHUCKWORM AND ITS PARASITES


DATE


MOTHS


1958--3 cages
March 13
April
May
Totals


1959--4 cages
February 17
March
April
May
Totals


1960--4 cages
March 10
April
May
Totals


284
3375
391
4050


2
410
2392
65
2869


92
3334
154
3580


1966--3 cages
March 21 440
April 1104
May 59
Totals 1603


PARASITES


41
94
4
139


34
314
126
0
474


% PARASITES


12.6
2.7
1.0
3.3%


94.1
43.3
5.0
0.0
14.7%


20.6
0.6
0.0
1.2%


24
21
0
45


374
143
1
518


45.9
11.4
1.6
24.4%


DATE




Full Text

PAGE 1

~ ~ 7BIG BEND HORTICULTURAL LABORATORY MONTICELLO$ FLORIDA Big Bend Hart'. Lab. Mimeb Report BBL 67-7 March 31, 1967 APR 18 fiGENCE, 0F OVERWINTERING SHUCKWORM IN NORTH FLORIDA -by J. W. Van Duyn1 Emergence records of the overwintering generation of hickory shuckworm, Laspeyresoa caryania, were taken in the years 1958, 1959, 1960, and 1966. Three and one half bushels of infested pecan shucks were placed in each cage. Infested shucks were collected when they began separating from the nut, but before the shuck had turned brown. Daily records were taken from each cage when adults of the shuckworm and parasites began emerging in the next spring. In 1958 the first emergence was noted on March 13, and peak emergence was throughout April. About 85% of all moths emerged in April. Emergence in 1959 began on February 17, and peak emergence was in the second and third week in April, About 80% of all moths emerged in April. In 1960 emergence was first noted on March 10, and peak emergence occurred during the first three weeks in April. April's emergence accounted for about 93% of all emergence. Emergence in 1966 began on March 21, and peak emergence was during the first three weeks in April when about 65% of all moths emerged. Hymenoptera and diptera parasites were noted to attack shuckworm larva. Parasites emerged before the majority of shuckworm moths had emerged. The highest number of parasites collected was in 1966, when parasites accounted for 24,4% of all insects emerging. In 1958, 1959, and 1960, the percentage of parasites was 3.3%, 14.7%, and 1.2% respectively. Hymenoptera parasites were generally greater in number than diptera parasites. Shuckworm adults emerging in March and April lay eggs on nuts of native hickory. Usually two generations develop in hickory before pecan nuts are large enough to attack. Second generation adults lay eggs on the side of pecan nuts. Soon after hatching, the larva penetrates the nut at which time the nut drops. The first nut drop in 1966 was noted on July 2, 45 days earlier than the recommended spray dates. Insecticide tests were conducted using EPN, thiodan, dieldrin, parathion, malathion, and guthion. EPN and guthion applied three times from August 1, and two and four weeks later gave good results. All other insecticides tested did not give satisfactory results. Check plots were very heavily infested. 1 Research Associate in Entomology, Big Bend Horticultural Laboratory, Monticello, Florida. 200 cc

PAGE 2

-2EMERGENCE oF OVERWINTERING SHUCKWORM AND ITS PARASITES DATE MOTHS PARASITES % PARASITES 1958-3 cages March 13 284 41 12.6 April 3375 94 2.7 May 391 4 1.0 Totals 4050 139 3.3% 1959-4 cages February 17 2 34 94.1 March 410 314 43.3 April 2392 126 5.0 May 65 0 0.0 Totals 2869 474 14.7% 1960-4 cages March 10 92 24 20.6 April 3334 21 0.6 May 154 0 0.0 Totals 3580 45 1.2%o 1966-3 cages March 21 440 374 45.9 April 1104 143 11.4 May 59 1 1.6 Totals 1603 518 24.4%