WOUND-INDUCED ANTIXENOTIC RESISTANCE TO FLEA BEETLES, PHYLLOTRETA CRUCIFERAE (GOEZE) (COLEOPTERA: CHRYSOMELIDAE), IN CRUCIFERS

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.

1993 ◽  
Vol 125 (4) ◽  
pp. 703-713 ◽  
Author(s):  
R.J. Lamb ◽  
P. Palaniswamy ◽  
K.A. Pivnick ◽  
M.A.H. Smith

AbstractFive cycles of single-plant and progeny-row selection in lines derived from Brassica rapa L. "Tobin" were used to identify plants with incomplete resistance to flea beetles, Phyllotreta cruciferae (Goeze). This line, called C8711, had higher survival, grew larger, and yielded more seed than Tobin when the two lines were compared in field plots at Glenlea, Manitoba, unprotected by insecticide. C8711 without insecticide yielded more seed than Tobin treated with a lindane seed dressing, but less than Tobin treated with carbofuran granules. With carbofuran, which prevents most flea beetle damage, the yield of C8711 was 35% higher than for Tobin. At Saskatoon, Saskatchewan, the differences between C8711 and Tobin were not statistically significant, although the trends were similar to those at Glenlea. C8711 was late maturing, produced small seed, and was not of canola quality. The resistance in C8711 is attributed to a low level of antixenosis, rapid growth at the cotyledon stage, and tolerance to damage during the first 3–4 weeks of growth.


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


1980 ◽  
Vol 60 (4) ◽  
pp. 1439-1440 ◽  
Author(s):  
R. J. LAMB

Pods of the mustard Brassica hirta ’Gisilba’, which have stiff hairs, showed no significant flea beetle damage, while adjacent rapeseed plots showed heavy pod damage. Removal of hairs from mustard pods caused an increase in feeding damage by the flea beetles. Breeding for pod hairiness in rapeseed may reduce pod damage caused by this pest to an insignificant level.


1988 ◽  
Vol 68 (1) ◽  
pp. 85-93 ◽  
Author(s):  
R. J. LAMB

A 5-yr field study to develop a method for assessing the susceptibility of crucifer seedlings to damage by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) is described. The recommended method consisted of five replicate 5-m rows per cultivar in a randomized complete-block design. Each test was sown three times at weekly intervals, to assure that at least one test received an appropriate level of flea beetle damage. Each test was assessed 4–5 wk after seeding by counting the number of surviving seedlings in each row and by weighing the dried aboveground portion of 10 randomly selected seedlings, although the latter discriminated fewer lines. The damage caused by flea beetles varied spatially, but this source of variation was minor and did not compromise the tests. This method proved adequate for discriminating among crucifer species and agronomically similar cultivars, some of which showed consistent, significant differences in their responses to flea beettle damage.Key words: Crucifer, rapeseed, flea beetle, pest 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.


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


Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 286
Author(s):  
David George ◽  
Gordon Port ◽  
Rosemary Collier

The use of trap crops to manage pest insects offers an attractive alternative to synthetic pesticides. Trap crops may work particularly well at smaller production scales, being highly amenable where crop diversification and reduction of synthetic inputs are prioritised over yield alone. This paper describes a series of experiments. The first was to demonstrate the potential of turnip rape (Brassica rapa L., var. Pasja) as a trap crop to arrest flea beetles (Phyllotreta spp.) to protect a main crop of cauliflower (Brassica oleracea L., var. Lateman). The subsequent experiments explored two possible approaches to improve the function of the trap crop—either by separating trap and main crop plants spatially, or by introducing companion plants of tomato (Lycopersicon esculentum Mill., cv Amateur) into the main crop. In caged field experiments, feeding damage by flea beetles to crop border plantings of turnip rape far exceeded damage to cauliflower plants placed in the same position, indicating a “trap crop effect”. Neither turnip rape plants nor cauliflower as a border significantly reduced flea beetle damage to main crop cauliflower plants, although the numbers of feeding holes in these plants were lowest where a turnip rape border was used. In similar cages, leaving gaps of 3–6 m of bare soil between turnip rape and cauliflower plants significantly reduced feeding damage to the latter, as compared to when plants were adjacent. The results of a small-scale open field trial showed that a turnip rape trap crop alone reduced flea beetle damage to cauliflower, significantly so later in the season at higher pest pressures, but that addition of tomato companion plants did not improve pest control potential.


1991 ◽  
Vol 71 (1) ◽  
pp. 13-20 ◽  
Author(s):  
R. P. Bodnaryk ◽  
R. J. Lamb

Antixenosis (nonpreference) and tolerance were identified as two mechanisms of resistance in seedlings of mustard, Sinapis alba 'Ochre', that likely account for the high level of resistance that this plant shows to flea beetles, Phyllotreta cruciferae Goeze, in the field. Sinapis alba showed antixenosis in no-choice and choice feeding tests with a susceptible species, Brassica napus 'Westar'. The beetles consumed about twice as much of the B. napus foliage as compared with S. alba. The highest level of antixenosis occurred in younger seedlings, indicating that S. alba puts forth an optimum defense when it is most vulnerable to flea beetle herbivory. Seedlings of S. alba were tolerant of low levels of flea beetle feeding damage to their cotyledons and continued to grow at almost the same rate as undamaged seedlings, whereas the growth of B. napus declined continuously with the level of feeding damage. The level of tolerance shown by S. alba combined with antixenosis probably accounts for the resistance reported for this crop in the field. In comparison with S. alba, B. napus seedlings, which show no tolerance and are preferred hosts, succumb rapidly to flea beetle attack unless protected with an insecticide. Key words: Insect resistance, mechanism, flea beetle, seedling, mustard, Sinapis alba


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


2007 ◽  
Vol 139 (4) ◽  
pp. 534-544 ◽  
Author(s):  
R.H. Elliott ◽  
M.C. Benjamin ◽  
C. Gillott

AbstractLaboratory experiments were conducted to evaluate the contact and oral toxicity of commercial formulations of spinosad and deltamethrin to adults of the crucifer flea beetle, Phyllotreta cruciferae (Goeze). Method of exposure had a significant effect on flea beetle mortality and feeding damage to canola seedlings. Topical treatment of flea beetles with deltamethrin or different concentrations of spinosad resulted in significantly lower mortality and higher feeding damage than exposure to treated canola cotyledons. Results indicated that spinosad was more toxic by ingestion than by topical contact. Mortality from treated cotyledons was significantly higher with 60 ppm deltamethrin than with 80 or 120 ppm spinosad after 24 h exposure but not after 120 h exposure. Delayed mortality in the spinosad treatments did not result in high feeding damage; damage after 120 h was not significantly different in the spinosad and deltamethrin treatments. Low concentrations of spinosad (40 ppm) strongly inhibited feeding activity within 24 h after exposure. Mortality from spinosad was higher after beetles were exposed to treated cotyledons for 120 h than for 24 h. Mortality from spinosad, but not deltamethrin, was significantly higher at 25 °C than at 15 °C. An ionic surfactant, polyethylenimine, increased the toxicity of 40 ppm spinosad. Our study suggests that spinosad has potential for use as an insecticide against crucifer flea beetles on canola.


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