ANTIBIOSIS OF PREFERRED AND NON-PREFERRED HOST-PLANTS FOR THE FLEA BEETLE, PHYLLOTRETA CRUCIFERAE (GOEZE) (COLEOPTERA: CHRYSOMELIDAE)

1997 ◽  
Vol 129 (1) ◽  
pp. 43-49 ◽  
Author(s):  
P. Palaniswamy ◽  
R.J. Lamb ◽  
R.P. Bodnaryk

AbstractThe antibiosis of crucifers to flea beetles, Phyllotreta cruciferae (Goeze), was compared for Brassica juncea L., B. napus L., and B. rapa L. with low antixenosis, B. carinata L. and Sinapis alba L. with moderate antixenosis, and Thlaspi arvense L. with high antixenosis. Adult flea beetles collected from the field in early spring fed actively on intact or excised leaves of all plants except T. arvense. The beetles survived, and gained weight and fat on the Brassica species and S. alba, but not on intact foliage of T. arvense. No antibiosis was detected in any of the Brassica species or in S. alba. Intact foliage of T. arvense was so antixenotic that beetles probably starved rather than suffered from antibiosis. A low level of antibiosis was detected in excised foliage of T. arvense where the antixenosis was lost. These experiments show that estimates of beetle survival, dry weight, and fat content can be used in the laboratory to test small numbers of candidate plants for antibiosis. However, the level of antibiosis appears to vary less among Brassica species and related plants than does the level of antixenosis, and so the latter is a more promising type of resistance for use against flea beetles in canola.

2000 ◽  
Vol 80 (4) ◽  
pp. 881-887 ◽  
Author(s):  
J. E. Gavloski ◽  
U. Ekuere ◽  
A. Keddie ◽  
L. Dosdall ◽  
L. Kott ◽  
...  

All currently registered varieties of canola/oilseed rape, Brassica napus and B. rapa, are susceptible to attack by flea beetles, although to varying degrees. The development of resistant cultivars would be an environmentally acceptable means to reduce the damage caused by flea beetles. Seedlings from 10 species of Brassicaceae were evaluated for levels of antixenosis resistance to flea beetles in the laboratory, along with 308 Sinapis alba/B. napus hybrids. Thlaspi arvense and 11 cultivars of S. alba were resistant to feeding by flea beetles. In addition, 34 S. alba/B. napus hybrids were resistant to feeding by flea beetle in at least one test, although many of these failed to demonstrate resistance with repeated testing. One hybrid line was resistant to feeding by flea beetles each of the four times it was tested, while another was resistant in three out of four tests. These data indicate that resistance to flea beetles within the Brassicaceae is a genetic trait and can be transferred by interspecific hybridization. This information is the first step towards introgression of genetic sources of flea beetle resistance from resistant relatives into canola varieties. Key words: Flea beetles, Phyllotreta cruciferae, Brassica, resistance, antixenosis, introgression


1993 ◽  
Vol 125 (5) ◽  
pp. 903-912 ◽  
Author(s):  
P. Palaniswamy ◽  
R.J. Lamb

AbstractLaboratory experiments were conducted to determine the effect of wounding the cotyledons of Sinapis alba L. cv. Ochre, Brassica napus L. cv. Westar, B. rapa L. cv. Tobin, and C8711, a selection from Tobin, on subsequent feeding damage by the flea beetle, Phyllotreta cruciferae (Goeze). Cotyledons of 7-day-old seedlings were wounded either by puncturing them with needles (mechanical wounding) or by exposing them to flea beetles. One, 2, or 9 days following wounding, the wounded and unwounded seedlings were exposed to flea beetles and the feeding damage was estimated as a measure of antixenosis. Mechanical wounding of one of the cotyledons with 96 needle punctures induced a significant reduction in the damage of the unwounded cotyledons of S. alba, 1 or 2 days following wounding. True leaves of the wounded seedlings also showed consistently less damage than unwounded controls, 9 days following wounding. In S. alba, all three levels of mechanical wounding (i.e. 6, 24, or 96 punctures per cotyledon) reduced subsequent flea beetle damage to a similar extent. Wrapping a cotyledon of S. alba with a plastic film produced an effect similar to wounding it with needles. As with mechanical wounding, flea beetle wounding also reduced subsequent flea beetle damage in S. alba. Other plant species (B. napus and B. rapa) tested showed no measurable induced effects on subsequent feeding damage.


1998 ◽  
Vol 130 (3) ◽  
pp. 385-386 ◽  
Author(s):  
P. Palaniswamy ◽  
F. Matheson ◽  
R.J. Lamb

Water stress, especially wilting, can increase the susceptibility of plants to herbivory by insects (Holtzer et al. 1988). Insects as diverse as locusts and leaf-cutting ants prefer wilted foliage (Bernays and Lewis 1986; Vasconcelos and Cherrett 1996). Palaniswamy et al. (1997) observed that the crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), fed on excised and wilted foliage of Thlaspi arvense L. (Cruciferae) but not on intact and turgid foliage. If water stress can make unpalatable plants more palatable, identifying robust resistance to pests such as flea beetles will be difficult. The purpose of this study was to determine whether wilting affects feeding by the crucifer flea beetle and in particular if wilting differentially affects feeding on preferred and nonpreferred plants.


1991 ◽  
Vol 71 (2) ◽  
pp. 397-404 ◽  
Author(s):  
R. P. Bodnaryk ◽  
R. J. Lamb

Seedlings of Brassica napus L. 'Westar' or Sinapis alba L. 'Ochre' grown from seeds of various size were offered to flea beetles, Phyllotreta cruciferae (Goeze) in feeding tests for damage assessment. The proportion of cotyledon area damaged in both species was highest for seedlings grown from small seeds in choice and no-choice feeding tests. The proportion of seedlings killed by flea beetle feeding was also highest in seedlings from small seeds, an effect that was especially pronounced at high beetle densities (10/seedling) where 100% of seedlings from small seeds of B. napus were killed compared to 28.3% of seedlings from big seeds. For S. alba, at 20 beetles/seedling, 45.4% of seedlings from small seeds were killed compared to only 9.1% of seedlings from big seeds. Seedlings grown from big seeds of S. alba tolerated low levels of damage caused by flea beetle feeding or by scissors. No evidence for tolerance was obtained for seedlings from small seeds of S. alba or for seedlings from big or small seeds of B. napus. "Big seeds" appears to be a desirable trait that enhances crucifer seedling resistance to flea beetle attack and results in increased seedling survival. Key words: Brassica napus 'Westar', Sinapis alba 'Ochre', Phyllotreta cruciferae, flea beetle, seed size, resistance


1992 ◽  
Vol 124 (5) ◽  
pp. 895-906 ◽  
Author(s):  
P. Palaniswamy ◽  
R.J. Lamb ◽  
P.B.E. McVetty

AbstractA laboratory method to screen crucifer seedlings for antixenosis resistance to flea beetles, Phyllotreta cruciferae (Goeze), is described. The method utilizes a plexiglass arena with a foam base to hold 30- by 50-mm vials containing individual seedlings of 10 entries (10 seedlings per entry) in a 10 × 10 layout. In each arena, nine test entries and a standard entry are compared in a Latin square design. Flea beetles are allowed to feed on seedlings for about 30 h, and then the damage to individual seedlings is estimated using a visual rating scale. A rating of one arena can be completed in about 15 min. Seedlings at the arena edge often suffer more damage than those in the centre of the arena, but the effect of this variability in damage is minimized by the Latin square design. Use of border (guard) rows and columns does not eliminate the edge effects. The use of arenas without borders, and a single damage rating where the damage to the standard entry is about 50% of the cotyledon area, are considered ideal for initial screening to identify sources of flea beetle resistance. The method detects entries that differ by as little as 18% damage using a single arena with 10 replicate seedlings per entry. No significant antixenosis was found among 19 cultivars of Brassica napus L. and B. campestris L., but one accession of B. carinata L. and two accessions of Sinapis alba (L.) exhibited antixenosis.


1986 ◽  
Vol 118 (1) ◽  
pp. 79-80
Author(s):  
L. Burgess ◽  
C.F. Hinks

In 1982, the synthetic pyrethroid, cypermethrin, was among the insecticides recommended as a spray for control of adult flea beetles attacking canola crops in Saskatchewan (Saskatchewan Agriculture 1982). Growers reported some problems with its effectiveness at the recommended rates of 14–20 g AI/ha, however, and the recommendation for its use against flea beetles was subsequently discontinued. Laboratory spray trials were begun in 1982 to determine if post-treatment temperature affected the contact toxicity of cypermethrin to adults of the major pest species, Phyllotreta cruciferae (Goeze), and if the dosage that had been recommended was adequate as a contact spray.


1980 ◽  
Vol 112 (7) ◽  
pp. 745-746 ◽  
Author(s):  
L. Burgess

Several instances of predation by lacewing larvae on adults of the flea beetle Phyllotreta cruciferae (Goeze) have been observed in Saskatchewan. Other reported insect predators of rapeseed-crop-infesting flea beetles in the Canadian prairie provinces are the beetle Collops vittatus Say (Gerber and Osgood 1975), and one of the big-eyed bugs, Geocoris bullatus (Say) (Burgess 1977).The first observation of an attack on an adult flea beetle by a lacewing larva was in August 1972, when some lacewing larvae, adult flea beetles, diamondback moth larvae (Plutella xylostella (L.)) and unidentified aphids and midges were swept from maturing rapeseed near Aberdeen, Saskatchewan. One of these lacewing larvae attacked an adult of P. cruczferae in a glass collecting-vial and carried the flea beetle around in its jaws. Other lacewing larvae attacked aphids, midges, and diamondback moth larvae. Further evidence for lacewing larvae feeding on adult flea beetles was obtained in August 1979, when a sizeable population of lacewing larvae in a rapeseed crop was encountered near St. Gregor, Saskatchewan. One of the larvae swept from this crop had an adult of P. cruciferae in its jaws when it was first seen in the sweep net. Later the same day, another lacewing larva, swept from a nearby rapeseed field, attacked an adult of P. cruciferae in a collecting vial. In the laboratory both lacewing larvae, still carrying their prey, were quick-frozen, preserved in 70% ethanol and later photographed.


1997 ◽  
Vol 77 (2) ◽  
pp. 283-287 ◽  
Author(s):  
Robert P. Bodnaryk

Foliar concentrations of the predominant glucosinolates in the mustards B. juncea (allyl glucosinolate, sinigrin) and S. alba (p-hydroxybenzyl glucosinolate, sinalbin) were determined in lines that had been selected in breeding programs for low levels of glucosinolates in their seeds for the oilseed market. The glucosinolate concentrations found in the cotyledons and leaves of the selected lines were also low, often by three or more orders of magnitude, compared with the unselected parent. The flea beetle, Phyllotreta cruciferae Goeze, and the diamondback moth, Plutella xylostella (L.), (both crucifer specialists) fed at equal rates on B. juncea and its low-glucosinolate lines, indicating that these species are insensitive to sinigrin and suggesting that their pest status on low-glucosinolate lines of B. juncea will likely remain unchanged. By contrast, the bertha armyworm, Mamestra configurata Wlk. (a generalist) fed up to fivefold more on the leaves of low-glucosinolate lines, suggesting that its pest status on low-glucosinolate B. juncea is likely to worsen relative to the mustard B. juncea. Flea beetles, diamondback moth, and the bertha armyworm fed at equal rates on the mustard S. alba and a low-glucosinolate line indicating that the status of these pests on low-glucosinolate S. alba will unlikely be much different from the mustard S. alba.Lines of S. alba differing in their sinalbin concentration by 1000-fold had equal levels of antixenosis resistance in their cotyledons against flea beetles, leaving little doubt that this resistance is independent of glucosinolates. Flea beetle resistance was also detected in the cotyledons of a low-glucosinolate line of B. juncea. The resistance was not detected in the parental line or in another low-glucosinolate line and appears to have arisen fortuitously during crossing and selection. Since resistance occurs in a line with concentrations of sinigrin three or more orders of magnitude lower than non-resistant lines, this resistance is also unlikely to be glucosinolate based. The mustards S. alba and B. juncea are a useful source of cotyledon resistance against flea beetles that is compatible with the aims of oilseed breeding. Key words: Glucosinolate, Brassica juncea, Sinapis alba, Phyllotreta cruciferae, Plutella xylostella, Mamestra configurata, resistance, mustard, canola, insect


1977 ◽  
Vol 109 (1) ◽  
pp. 21-32 ◽  
Author(s):  
L. Burgess

AbstractAdults of five species of flea beetles were found attacking rape crops (Brassica napusL. andBrassica campestrisL.) in the Canadian prairie provinces from 1971 to 1974.Phyllotreta cruciferae(Goeze) was the most abundant and serious pest, followed in order byPsylliodes punctulataMelsh. andPhyllotreta striolata(F.) (=vittata(F.)), whilePhyllotreta albionica(Lec.) andPhyllotreta robustaLec. were present only occasionally. The fourPhyllotretaspecies confined their feeding largely to cruciferous plants, butPsyl.punctulatahad a broader host range. All of the five species overwintered as adults, usually in leaf litter or turf beneath hedges, poplar groves, or fencerows, or sometimes in the soil in fields, and all became active with the arrival of warm sunny weather in the spring, withPsyl.punctulatausually being the first to appear. All appeared to have but one generation per year, with mating and egg laying occurring in the spring, the larvae inhabiting the soil and feeding on host-plant roots, and the new generation of adults emerging from pupae in the soil in late July and in August. The overwintered adults usually died in late June or early July, so there was a period in July when adult flea beetles were scarce. The most serious damage to rape crops by flea beetles was caused by overwintered adults attacking seedling crops in the spring; movement of these beetles into crops took the form of a creeping infestation moving from plant to plant into the field from nearby volunteer rape of cruciferous weed feeding grounds, or a more rapid and even infestation of a whole field with flight probably being the major method of movement. Flea beetles fed most actively when the weather was sunny, warm, and dry; cool damp weather reduced the intensity of attack and aided plant growth. Shade, such as exists in a healthy stand of rape beyond the pre-bloom stage, also inhibited attack. Occasionally, late-maturing rape crops were damaged in late summer by new generation adult flea beetles, particularlyP.cruciferae, feeding on the green epidermis of the stems, leaves, and pods.A field key for separating the five flea beetle species attacking rape crops in the Canadian prairie provinces is given.


2007 ◽  
Vol 87 (2) ◽  
pp. 385-393 ◽  
Author(s):  
R. H. Elliott ◽  
L. W. Mann ◽  
O. O. Olfert

A 3-yr study was conducted on three synthetic Brassica rapa L. cultivars to determine the effects of seed size and seed weight on seedling establishment, seedling growth and susceptibility to feeding damage by flea beetles, Phyllotreta spp. (Coleoptera: Chrysomelidae). Seed lots of AC Boreal, Fairview and Hysyn 110 were sieved to obtain small, medium and large seeds (1.4–1.6, 1.6–1.8 and 1.8–2.0 mm, respectively). In the laboratory, seedlings grown from large seeds had the largest cotyledons, highest shoot dry weight and highest biomass. Shoot weights increased as seed size increased. Sized seeds of the three cultivars were grown in the field without insecticides in 1998–2000. Seedlings of small seeds had the highest flea beetle damage and poorest seedling establishment. Shoot dry weight and biomass 14–35 d after planting increased as seed size and seed weight increased. Compared with small seeds, large seeds improved shoot dry weight, biomass and seed yield by 13–43, 25–57 and 12%, respectively. Results indicated that seedlings of medium and large seeds are more vigorous and tolerant to flea beetle damage than seedlings of small seeds. Tolerance was due to a higher initial seedling weight rather than higher relative growth rate. Shoot dry weights, biomass and yield of the three cultivars were more strongly correlated with 1000-seed weight than with seed diameter. Key words: Canola, flea beetles, seed size, seedling vigour, tolerance, seed weight


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