Biology of the Diamondback Moth, Plutella maculipennis (Curt.) (Lepidoptera: Plutellidae), in Eastern Ontario III. Natural Enemies

1960 ◽  
Vol 92 (6) ◽  
pp. 419-428 ◽  
Author(s):  
D. G. Harcourt
Keyword(s):  
Environmental Factors ◽  
Relative Abundance ◽  
Natural Enemies ◽  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Cabbage Looper ◽  
Eastern Ontario

The diamondback moth, Plutella maculipennis (Curt.), is a sporadic pest of cruciferous crops throughout Canada. It is normally held in check by a multiplicity of environmental factors, chiefly biotic; however, serious outbreaks do occur (MacNay, 1948, 1953, 1957, 1959). In eastern Ontario it has been extremely numerous since late 1951, and during the present study, 1952 – 1956, it was more abundant than the imported cabbageworm, Pieris rapae (L.), or the cabbage looper, Trichoplusia ni (Hbn.) . Two earlier papers (Harcourt, 1956, 1957) presented the history, distribution, and synonymy of the insect, giving general descriptions of the stages and many aspects of its biology in eastern Ontario. This article gives the relative abundance of its parasites and predators, and discusses certain population relationships.

Abundance and Relative Importance of Caterpillars Attacking Cabbage in Eastern Ontario

1955 ◽  
Vol 87 (9) ◽  
pp. 400-406 ◽  
Author(s):  
D. G. Harcourt ◽  
R. H. Backs ◽  
L. M. Cass
Keyword(s):  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Economic Importance ◽  
The Other ◽  
Cabbage Looper ◽  
Relative Importance ◽  
Four Seasons ◽  
Large Numbers ◽  
Eastern Ontario

Cabbage and related crops are attacked every year throughout Ontario by caterpillars of three species, namely, the imported cabbageworm, Pieris rapae (L.), the diamondback moth, Plutella maculipennis (Curt.), and the cabbage looper, Trichoplusia ni (Hbn.). The imported cabbageworm is generally regarded as the most abundant of the three species and is reported as doing damage of considerable economic importance each year. The cabbage looper does not occur in large numbers until late in the season, but in most years it is believed to be second only in importance to the imported cabbageworm. The diamondback moth is generally considered to be much less important than the other two species (Caesar, 19i8). As previously reported (Matthewman et al., 1952), these beliefs were not borne our by observations of field populations at Ottawa in 1950. Whereas populations of the cabbage looper were strikingly low, those of the diamondback moth were much higher than the literature indicated. This paper is a summary of four seasons' experiments, 1951-1954, undertaken to assess the abundance and relative importance of the three species in eastern Ontario.

AN ACTION THRESHOLD FOR CONTROL OF LEPIDOPTEROUS PESTS OF CABBAGE IN PRINCE EDWARD ISLAND

1994 ◽  
Vol 126 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Andrew P. Dornan ◽  
Jeff G. Stewart ◽  
Mark K. Sears
Keyword(s):  
Plutella Xylostella ◽  
Trichoplusia Ni ◽  
Prince Edward Island ◽  
Growth Stage ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Cabbage Looper ◽  
Fresh Market ◽  
Action Threshold ◽  
Insect Populations

AbstractAction thresholds for imported cabbageworm, Pieris rapae (L.), diamondback moth, Plutella xylostella (L.), and cabbage looper, Trichoplusia ni (Hübner), were evaluated on two cultivars of cabbage, Brassica oleracea var. capitata (L.), in Prince Edward Island. Thresholds were tested on plots of mid-season cabbage, cv. Minicole, and late-season cabbage, cv. Lennox, both grown for fresh market in 1991 and 1992. Management of larval populations at a threshold of 0.25 Cabbage Looper Equivalents (CLE) per plant resulted in yields equal to those obtained with bi-weekly applications or grower treatments. Higher thresholds of 0.50 and 1.0 CLE per plant were not as useful and did’ not consistently result in yields greater than untreated plots. Use of the threshold of 0.25 CLE per plant reduced the number of applications of insecticides by 30% compared with spraying insecticide at bi-weekly intervals from heading to harvest, and 43% compared with management by the grower without regard to insect populations or growth stage of the crop.

APPLICATION OF THE CABBAGE LOOPER EQUIVALENT MODEL TO LEPIDOPTEROUS PESTS OF BRUSSELS SPROUTS IN PRINCE EDWARD ISLAND

1994 ◽  
Vol 126 (4) ◽  
pp. 961-969 ◽  
Author(s):  
Andrew P. Dornan ◽  
Jeff G. Stewart ◽  
Mark K. Sears
Keyword(s):  
Trichoplusia Ni ◽  
Prince Edward Island ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Management Strategies ◽  
Abundant Species ◽  
Cabbage Looper ◽  
Equivalent Model ◽  
Brussels Sprouts ◽  
High Yields

AbstractAn investigation into the use of thresholds based on Cabbage Looper Equivalents (CLE) was conducted on Brussels sprouts, Brassica oleracea var. gemmifera (L.), cv. Valiant, grown in Prince Edward Island in 1991 and 1992. The CLE model was used to equate foliage consumption by larvae of the imported cabbageworm, Pieris rapae (L.), the diamondback moth, Plutella xylostella (L.), and the cabbage looper, Trichoplusia ni (Hübner). Management strategies included the following: (1) an untreated check; applications of insecticides after thresholds of (2) 1.0 CLE; (3) 0.50 CLE; or (4) 0.25 CLE per plant were exceeded; (5) bi-weekly applications of insecticides; and (6) applications of insecticides according to the grower’s spray schedule.In 1991, the imported cabbageworm was the most abundant species in the complex attacking the crop and high yields were obtained in all treatments. However, in 1992, the diamondback moth was the principal species and significantly reduced marketable yields in all treatments. Use of CLE as a model for threshold determination in the crop of Brussels sprouts underestimated the potential of the diamondback moth for damage and resulted in improper timing of applications of insecticide for adequate control of the diamondback moth.

scholarly journals Seasonal occurrence of three Lepidoptera on broccoli and effectiveness of planting date as a pest management tool in southeastern New Brunswick

2005 ◽  
Vol 79 (3) ◽  
pp. 129-137 ◽  
Author(s):  
P.M. Maltais ◽  
J.R. Nuckkle ◽  
P.V. LeBlanc
Keyword(s):  
New Brunswick ◽  
Pest Management ◽  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Planting Date ◽  
Cabbage Looper ◽  
Management Tool ◽  
Larval Population ◽  
Lepidoptera Noctuidae

Seasonal variations in abundance of three lepidopterous pests, the diamondback moth, Plutella xylostella [Lepidoptera : Plutellidae], the imported cabbageworm, Pieris rapae [Lepidoptera : Pieridae], and the cabbage looper, Trichoplusia ni [Lepidoptera : Noctuidae], were monitored over two years in broccoli plantings (Brassica oleracea var. italica) in southeastern New Brunswick. Four population peaks of imported cabbageworm were seen in 1990 and 1991 with 92 and 99% of the total larval population, respectively, being recorded during the latter part of the season, after 23 July. Four population peaks were also recorded for the diamondback moth in 1990 and 1991 with 81 and 97%, respectively, of the population being recorded after 23 July. Populations of cabbage looper appeared later in the season and because of low numbers were more difficult to assess. Using cabbage looper equivalents (CLE), the effectiveness of planting date as a pest management tool was also studied. Early crops have lower mean CLE per plant

Timing of DDT Applications for Control of Caterpillars on Cabbage

1952 ◽  
Vol 84 (11) ◽  
pp. 346-352 ◽  
Author(s):  
W. G. Matthewman ◽  
D. G. Harcourt ◽  
J. P. Perron
Keyword(s):  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Cabbage Looper ◽  
Severe Damage ◽  
Four Seasons

Three species of caterpillars commonly attack cabbage at Ottawa, namely, the imported cabbageworm, Pieris rapae (L.), the larva of the diamondback moth, Plutella maculipennis (Curt.) and the cabbage looper, Trichoplusia ni (Hbn.). All three species are readily controlled with DDT sprays or dusts but the timing of the applications is imporrant. Growers sometimes begin dusting or spraying too early, wasting one or more applications, or they delay the first application until mid-August, when severe damage has already occurred. This paper is a report on four seasons' experiments at Ottawa, 1947 to 1950, to determine the number and timing of applications of DDT required for control of caterpillars on late cabbage.

A Long-Term Survey of Parasitoid Species Composition and Parasitism of Trichoplusia ni (Lepidoptera: Noctuidae), Plutella xylostella (Lepidoptera: Plutellidae), and Pieris rapae (Lepidoptera: Pieridae) in Minnesota Cabbage

2005 ◽  
Vol 40 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Suzanne J. Wold-Burkness ◽  
W. D. Hutchison ◽  
Jana C. Lee ◽  
R. L. Hines ◽  
P. C. Bolin ◽  
...  
Keyword(s):  
Species Composition ◽  
Plutella Xylostella ◽  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Species Abundance ◽  
Cabbage Looper ◽  
Cotesia Glomerata ◽  
Pest Species ◽  
Pupal Parasitoids

Field studies were conducted near Rosemount, MN, during the years 1991–1994, 1996–1997, and 1999–2003, to assess the diversity of and parasitism by larval and pupal parasitoids of cabbage looper, Trichoplusia ni (Hübner), imported cabbageworm, Pieris rapae (L.), and diamondback moth, Plutella xylostella (L.). Species composition, parasitism rate, and species abundance (Hill's N1) were determined for each pest species. Voria ruralis (Fallen), Copidosoma floridanum (Ashmead), and Compsilura concinnata (Meigen) were the dominant parasitoids of T. ni; Phryxe pecosensis (Townsend), Cotesia glomerata (L.), and Pteromalus puparum (L.) are the dominant parasitoids of P. rapae; and Diadegma insulare (Cresson) is the dominant parasitoid of P. xylostella. In addition, the first records of the introduced parasitoid, C. concinnata, parasitizing T. ni and P. rapae, and Cotesia rubecula (Marshall) parasitizing P. rapae are documented for Minnesota.

scholarly journals Management of Diamondback Moth (Lepidoptera: Plutellidae) in Cabbage Using Collard as a Trap Crop

HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 875-879 ◽  
Author(s):  
E.R. Mitchell ◽  
Guangye Hu ◽  
Denise Johanowicz
Keyword(s):  
Brassica Oleracea ◽  
Natural Enemies ◽  
Trichoplusia Ni ◽  
Diamondback Moth ◽  
Cabbage Looper ◽  
High Concentration ◽  
Trap Crop ◽  
Collard Greens ◽  
Growing Seasons ◽  
Action Threshold

Collard greens (Brassica oleracea var. acephala L.) were planted in the peripheries of cabbage (Brassica oleracea var. capitata L.) fields in the spring growing seasons of 1997 and 1998 to evaluate their effectiveness as a trap crop to manage the diamondback moth (DBM) [Plutella xylostella (L.)]. The numbers of DBM never exceeded the action threshold for application of insecticides in any of the fields that were completely surrounded by collards, but did exceed the action threshold in three of the fields without collards on four sampling dates in 1998. In both years, the numbers of DBM larvae in the collards exceeded the action threshold of 0.3 total larvae/plant in eight of nine fields. Larval counts in cabbage surrounded with collards were not significantly higher than in the conventionally planted cabbage, even though the number of pesticide applications was reduced in the former. The few pesticide applications in fields surrounded by collards probably targeted the cabbage looper [Trichoplusia ni (Hübner)], which was not impeded by the collards from infesting the interior cabbage. There was no significant reduction in marketability, and damage to cabbage was similar to that in fields where collards were planted and in fields where only conventional pesticides were used. The reduced number of pesticide sprays, as well as the high concentration of host larvae in the collards, may help maintain populations of natural enemies of DBM in the agroecosystem. Planting collards in field peripheries is a potentially effective tactic to manage DBM in cabbage.

scholarly journals Management of Diamondback Moth (Lepidoptera: Plutellidae) in Cabbage Using Collard as a Trap Crop

2001 ◽  
Vol 11 (1) ◽  
pp. 150b-151
Author(s):  
E.R. Mitchell ◽  
Guangye Hu ◽  
Denise Johanowicz
Keyword(s):  
Brassica Oleracea ◽  
Natural Enemies ◽  
Trichoplusia Ni ◽  
Diamondback Moth ◽  
Cabbage Looper ◽  
High Concentration ◽  
Trap Crop ◽  
Collard Greens ◽  
Growing Seasons ◽  
Action Threshold

Collard greens (Brassica oleracea var. acephala L.) were planted in the peripheries of cabbage (Brassica oleracea var. capitata L.) fields in the spring growing seasons of 1997 and 1998 to evaluate their effectiveness as a trap crop to manage the diamondback moth (DBM) [Plutella xylostella (L.)]. The numbers of DBM never exceeded the action threshold for application of insecticides in any of thefields that were completely surrounded by collards, but did exceed the action threshold in three of the fields without collards on four sampling dates in 1998. In both years, the numbers of DBM larvae in the collards exceeded the action threshold of 0.3 total larvae/plant in eight of nine fields. Larval counts in cabbage surrounded with collards were not significantly higher than in the conventionally planted cabbage, even though the number of pesticide applications was reduced in the former. The few pesticide applications in fields surrounded by collards probably targeted the cabbage looper [Trichoplusia ni (Hübner)], which was not impeded by the collards from infesting the interior cabbage. There was no significant reduction in marketability, and damage to cabbage was similar to that in fields where collards were planted and in fields where only conventional pesticides were used. The reduced number of pesticide sprays, as well as the high concentration of host larvae in the collards, may help maintain populations of natural enemies of DBM in the agroecosystem. Planting collards in field peripheries is a potentially effective tactic to manage DBM in cabbage.

Responses of Diadegma insulare (Hymenoptera: Ichneumonidae) to Caterpillar Feeding in a Flight Tunnel

2001 ◽  
Vol 36 (3) ◽  
pp. 297-304 ◽  
Author(s):  
G. Y. Hu ◽  
E. R. Mitchell
Keyword(s):  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Flight Tunnel ◽  
Cabbage Looper ◽  
Larval Feeding ◽  
Plant Host ◽  
Generalist Herbivore ◽  
Diadegma Insulare ◽  
Host Complex

A flight tunnel bioassay was used to evaluate attraction responses of female Diadegma insulare (Cresson), a host-specific parasitoid of the diamondback moth, Plutella xylostella (L.), to collard plants (Brassica oleracea var. acephala L.) infested with host and nonhost caterpillars. Adult female wasps showed increased responses to odors of the plant-host complex after a brief contact experience with host-infested collard leaves. Such an increase shows evidence of associative learning in this parasitoid to the odor released from the larval-plant complex. The same experimental design was also used to determine responses of the parasitoid to plants infested with nonhost larvae-cabbage looper, Trichoplusia ni (Hübner), and imported cabbageworm, Pieris rapae (L.). The female wasps conditioned to the plants infested with host larvae also showed increased responses to plants infested with larvae of cabbage looper or imported cabbageworm. These results indicate that plants damaged by host and nonhost caterpillars may release general odors that are attractive to D. insulare. The general damage odors caused by host and nonhost larval feeding may enhance biological control of the diamondback moth. Host-search ability of the parasitoid increases after experiencing host damage. When host populations are low in fields, plant odors caused by generalist herbivore feeding may also attract D. insulare parasitoids to the vicinity, thereby improving encounter chances of the parasitoid encountering diamondback moth larvae.

Diamondback Moth (Lepidoptera: Plutellidae) Contamination of Cabbage Transplants and the Potential for Insecticide Resistance Problems

1996 ◽  
Vol 31 (3) ◽  
pp. 347-354 ◽  
Author(s):  
A. M. Shelton ◽  
M. K. Kroening ◽  
S. D. Eigenbrode ◽  
C. Petzold ◽  
M. P. Hoffmann ◽  
...  
Keyword(s):  
New York ◽  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Diamondback Moth ◽  
Management Strategies ◽  
Early Spring ◽  
Cabbage Looper ◽  
Southern United States ◽  
Field Samples ◽  
Contamination Levels

Samples collected from 1989 to 1992 document that the diamondback moth, Plutella xylostella (L.) was introduced into New York in early spring on cabbage, Brassica oleracea capitata (L.), transplants grown in the southern United States. During 1989, transplant shipments from five transplant companies in Florida, Georgia and Maryland were sampled for P. xylostella. In 1989, average seasonal infestations per transplant company ranged from 1.3 to 3.5 P. xylostella per 100 transplants. During June, when the majority of transplants arrived in New York, P. xylostella infestations were as high as 12.8 insects per 100 transplants on an individual shipment. Infestations by cabbage looper, Trichoplusia ni (Hübner), imported cabbageworm, Artogeia (=Pieris) rapae (L.), and cabbage webworm, Hellula rogatalis (Hulst), on an individual shipment were as high as 19.7 insects per 100 transplants. Compared with a standard susceptible field population, the P. xylostella which were collected from transplants demonstrated moderate to high (> than 100-fold in one case) levels of resistance to permethrin or methomyl. In 1990, average seasonal infestations per transplant company varied from 0.3 to 12.0 P. xylostella per 100 plants, but an individual shipment from Florida had 30.4 P. xylostella per 100 transplants. A population of P. xylostella collected in 1990 from Florida transplants had >200-fold resistance to methomyl. Despite intensive treatments, a New York grower who used the transplants with high contamination of resistant P. xylostella was unable to achieve acceptable control in his field. Samples collected from 1989 to 1992 from a transplant grower in Maryland indicate that better management in the field can reduce contamination levels to < 0.5%. The introduction of P. xylostella, especially those resistant to insecticides, on transplants poses a serious threat to cabbage growers and interregional management strategies should be adopted.

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