SEASONAL POPULATIONS OF THE DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA (LEPIDOPTERA: PLUTELLIDAE) IN RELATION TO DAY-DEGREE ACCUMULATION

1981 ◽  
Vol 113 (2) ◽  
pp. 127-131 ◽  
Author(s):  
R. A. Butts ◽  
F. L. McEwen

AbstractThe life history of Plutella xylostella (L.) was studied in plantings of Brussels sprouts at Cambridge, Ontario in 1977 and 1978. Adults were monitored by using sticky traps constructed of bristol board; eggs, larvae, and pupae were monitored by sampling plants. In both years in the spring, some of the first eggs were found before adults were caught in the traps. The trap collections indicated four periods of adult flight each year. During the last period of flight in 1977 eggs were laid; however, the fifth generation was not completed. Day-degree analyses of the populations indicated that 293 day-degrees (C) above a threshold temperature (7.3°C) were required to complete one generation. Using day-degree accumulations it was possible to predict accurately the periods when various stages of the pest were dominant even though there was considerable overlap of various stages in the field.

2013 ◽  
Vol 59 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Sergio A. De Bortoli ◽  
Alessandra M. Vacari ◽  
Roberto M. Goulart ◽  
Antonio S. Ferraudo ◽  
Haroldo X.L. Volpe

1984 ◽  
Vol 116 (7) ◽  
pp. 913-917 ◽  
Author(s):  
D. B. Smith ◽  
M. K. Sears

AbstractAlthough Plutella porrectella (L.) is similar in appearance to the diamondback moth, P. xylostella (L.), several aspects of its biology are quite different from its more common relative. P. porrectella completed two generations per year and overwintered as an early-instar larva within apical buds of dame's rocket, Hesperis matronalis (L.). Four instars were observed in larvae reared in the laboratory. An average of 30 days was required for completion of one generation at 25 °C. This species does not seem to be an alternative host for parasites of the diamondback moth as only a single parasitic wasp, Itoplectis conquisitor (Say), was reared from 228 larvae collected in the field.


1991 ◽  
Vol 69 (8) ◽  
pp. 2048-2058 ◽  
Author(s):  
Gordon F. Bennett ◽  
Terry L. Whitworth

The rate of development of the larvae, postfeeding larvae, puparia, and adults of 10 species of Protocalliphora were studied and differences noted in the rates of development and (or) survival. Larvae of Protocalliphora were photonegative and strongly influenced by thigmotactic stimuli. The method of feeding of the larva is described. Metamorphosis was completed more quickly at higher temperatures than at lower temperatures. Survival of purparia at temperatures of 7 °C or lower was poor and indicated that this stage was not adapted to withstand low temperatures and probably did not survive the winter. Adult Protocalliphora females were longer lived than males, surviving for an average of 70–100 days, with some individuals surviving for over 250 days under laboratory conditions. Adults fed readily on a sugar–protein diet, crushed berries, and certain species of flowers, but most species did not feed on any form of carrion. Adults mated readily in captivity, but none of the seven species tested crossbred. Spermatozoa remained motile in the seminal receptacles for over 100 days. Eggs were laid on a few occasions, but the factors determining egg production were not studied. Adult Protocalliphora were strongly photopositive and became quiescent in the dark. Adult flies rarely became active until a threshold temperature of 15.5 °C; different species had differing threshold temperatures. Adults successfully overwintered in a single field trial.


2020 ◽  
Author(s):  
Sergio Antonio De Bortoli ◽  
Wanderlei Dibelli ◽  
Dagmara Ramalho ◽  
Robério C S Neves ◽  
Caroline Placidi De Bortoli ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Roman Rakitov ◽  
Esther Appel

The world’s only member of Hemiptera Auchenorrhyncha known to form true galls, the leafhopperScenergates viridis(Vilbaste) (Cicadellidae), transforms leaves of camelthorn (Alhagi maurorumMedikus, Fabaceae) into pod-like chambers, up to 35 mm long, inside which individual leafhoppers develop, mate, and lay eggs. At the study site 40 km SE of Bukhara (Uzbekistan), two generations develop annually. First-instar nymphs cause young leaves to fold along the midrib. The subsequent development takes place inside the tightly closed growing gall, plugged at both ends with a mixture of leafhopper excrement, brochosomes, and crushed exuviae. These plugs act as mechanical barriers and sticky traps for intruders. The inner surface of the gall, lined with brochosomes and wax platelets, is hydrophobic. Adult males emerge from their galls and squeeze into female galls. Fertilized females insert an average of 146 eggs under the gall’s inner epidermis and remain inside, possibly protecting the brood, until they die. The walls of the galls containing eggs are approximately three times thicker than regular leaves. The galls are subject to predation by Gelechiidae caterpillars; the eggs of the leafhopper are parasitized by two species of Trichogrammatidae and one Mymaridae (Hymenoptera), and its larvae by one species of Pipunculidae (Diptera).


1998 ◽  
Vol 130 (2) ◽  
pp. 173-185 ◽  
Author(s):  
Claude Godin ◽  
Guy Boivin

AbstractEggs, larvae, and adults of diamondback moth, Plutella xylostella (L.), and imported cabbageworm, Artogeia rapae (L.), were monitored on cabbage, broccoli, and brussels sprouts [Brassica oleracea (L.) var. capitata, italica, and gemmifera] for 2 years in southwestern Quebec. The first eggs and adults of P. xylostella were observed during the first week of June, and the use of pheromone traps combined with plant sampling permitted detection of three to four generations on each cultivar type. However, adult counts in pheromone traps were not correlated with the number of eggs and larvae on plants. The date at which each generation appeared and their duration varied little between the three Brassica cultivars. An average of 352.7 degree-days (DD) above 7.3 °C were required to complete one generation, but the considerable overlap between generations reduced the usefulness of DD accumulations to predict P. xylostella occurrence. Visual counts of adult A. rapae and plant sampling of eggs and larvae permitted detection of three generations of this species on each cultivar type. The first A. rapae eggs were found during the last week of May, at least 2 weeks before adults were observed. However, butterfly counts were generally correlated with the number of larvae on plants. The dates at which each generation of A. rapae started were similar between cultivar types, and an average of 319.7 DD above 10.0 °C was required to complete one generation.


Sign in / Sign up

Export Citation Format

Share Document