We compared the effectiveness of three different trap colours (blue, yellow and white) to identify the optimal trap colour for the monitoring of the thrips Frankliniella intonsa, Thrips tabaci, Thrips fuscipennis and Aeolothrips intermedius in the three pea cultivars, namely Polar, Izolda and Tarchalska. The number of captured thrips specimens was significantly affected by trap colour, pea cultivar and interaction between these factors. The two most attractive trap base colours for thrips were blue (peak at 450 nm) and yellow (peak at 550 nm). Irrespective of the pea cultivar, most F. intonsa were captured on the blue and yellow traps. Blue traps were the most attractive to T. fuscipennis and T. tabaci, followed by yellow and white ones, and yellow traps were most attractive to A. intermedius. More thrips were caught on the traps located in the plots with cultivars characterised by a longer growing season Tarchalska and Izolda, which were inhabited by large numbers of thrips. There was a significant interaction effect between trap colour and pea cultivar on the number of caught F. intonsa and T. fuscipennis in both years and for T. tabaci in 2010. Overall, among the tested trap colours, blue traps were the most effective ones for monitoring thrips in pea fields and could be used as an early detection tool. Yellow traps may be risky because they reduce population densities of the predaceous A. intermedius in pea fields, thus leading to an increase in pest numbers.

No abstract

Field experiments on the susceptibility of onion to thrips infestation were carried out in 2012 and 2013. The investigation used 18 cultivars and 5 breeding lines of Allium cepa, and the species A. fistulosum and A. roylei. In 2012 A. fistulosum was one of the most infested plants, whereas in 2013 infestation was no more than average. The most infested cultivars of A. cepa were ‘Efekt’, ‘Alonso F1’, ‘Alibaba’ and ‘Wama’ and the ‘NOE5’ breeding line. In 2012 the extent of damage ranged from 12 to 55%, in 2013 from 20 to 30%. The ‘NOE2’, ‘NOE3’ and ‘Wama’ cultivars were the most seriously damaged by thrips. Leaf damage to A. fistulosum was minimal. No damage was caused to the wild species A. roylei by feeding onion thrips.

No abstract

Damage caused to cultivated carrots by the hawthorn-carrot aphid, Dysaphis crataegi Kalt. (Hemiptera: Aphididae) is one of the factors limiting carrot production in Poland. Planting resistant and tolerant cultivars could reduce yield losses due to the damage caused by this pest. This study was conducted to evaluate the resistance and/or tolerance of 10 carrot genotypes to hawthorn-carrot aphid. Their field resistance was determined under field conditions based on five indicators, namely, mean number of alates (migrants) per plant and mean percentage of plants colonized by them, mean seasonal number of aphids per plant, mean number of aphids per plant and mean percentage of infested plants at peak abundance. Antibiosis experiments were conducted under laboratory conditions and pre-reproductive, reproductive time, fertility, and demographic parameters, represented by the net reproduction rate (Ro), intrinsic rate of increase (rm) and mean generation time (T), were calculated. Five cultivars, Afro F1, Nipomo F1, Samba F1, White Satin F1, and Yellowstone showed field resistance. Antibiosis experiments revealed significant differences among the carrot cultivars in the length of the reproductive period, female fecundity in the time equal to the pre-reproduction time, and total progeny of hawthorn-carrot aphid. The intrinsic rate of natural increase (rm) for apterous aphids varied significantly, ranging between 0.181 (Nipomo F1) and 0.343 females/female/day (White Satin F1). Additionally, the estimated net reproductive rate (R0) was the lowest on Nipomo F1, and this genotype was determined to be resistant. Our results suggest that a very high density of trichomes on the leaf petioles (71.94 trichomes/cm2) could adversely affect the feeding, bionomy, and demographic parameters of hawthorn-carrot aphid on the cultivar Nipomo F1. In addition, Napa F1 and Kongo F1 demonstrated high tolerance. Considering all the results collectively, four genotypes, Afro F1, Kongo F1, Napa F1 and Nipomo F1, were relatively resistant/tolerant to the hawthorn-carrot aphid.

The polyphagous onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) is a serious pest in many protected and field crops and has recently been found to occur in high numbers in Pisum sativum L. crops. In the present study, the abundance of T. tabaci was compared on two pea cultivars in the field. Data on sweep net catches at different sampling times during the day suggest that peak activity of the thrips is at noon. Significantly more thrips larvae and adults were caught on the early pea cultivar Cud Kelwedonu compared with the very early cultivar Pionier, particularly during and after flowering of the peas. Analysis of primary plant compounds indicated that the higher leaf nitrogen and sucrose contents in the leaves of cvar Cud Kelwedonu promote thrips population growth in pea. The preference of T. tabaci for leaves of cvar Cud Kelwedonu was confirmed in experiments in the laboratory. Thrips tended to settle, caused significantly more feeding damage and laid significantly more eggs on the leaves of Cud Kelwedonu. Knowledge on abundance, activity patterns and host use of T. tabaci in pea may contribute to optimizing cultivar selection, monitoring and timing of possible control measures in the future.

Thrips tabaci Lindeman is a global pest and also represents a serious threat to onion production in Poland. In 2 years (2015–2016) of field studies, 8 onion cultivars were evaluated to characterize their susceptibility to onion thrips and to determine if leaf colour is associated with thrips preference. The actual count and the proportional abundance of adult thrips collected from onion leaves during plant colonization by insects were both used to express the preference of thrips for different onion cultivars. At the same time, the colour measurements were analysed by considering the CIELAB (CIE 1976 L*a*b*) and CIE L*C*h* colour spaces. There were distinct differences in the susceptibility of onion cultivars to colonization by onion thrips. Leaf colour coordinate values were correlated with attractiveness to thrips; typically, higher lightness (L*), yellowness (b*), chroma (C*), hue (h*), and lower redness (a*) attracted more thrips. We concluded that the vivid, intense green-yellowish leaf colour of susceptible varieties might have been the cause of the thrips preference observed. We also identified useful genotypes, Tęcza and Wenta, for host plant resistance to thrips and suggest a link between colour and antixenotic resistance. The resistant cultivars had darker, green-grey-yellowish leaves.

The aim of the present research work was to investigate the effect of orange and cinnamon oil on the occurrence and harmfulness of Thrips tabaci Lind on onion. In 2014, the nonchemical treatment was made with Prev-B2 (the concentration of 0.4%), which contains: 4.2% of orange oil, 2.1% of boron and product Canol 70% p/p exstract of Cinnamomum zeylanicum. In 2015, only Prev-B2 product was used. The standard sprayer was used and the treatments were done: twice in 2014 and three times in 2015. The thrips were collected directly from the leaves, using standard sweeping nets. The plants were examined to find the leave damages caused by feeding thrips. In 2014, Thrips tabaci was recorded from 11 June to 19 August, whereas in 2015 from 24 June to 4 August. Over two years of observations, the highest number of thrips was collected from onion growing on control plots (not treated with any preparation). Also, the mean percentage of areas damaged on the onion leaves was significantly higher on control plots than on plots treated with cinnamon oil in 2014 and orange oil in 2015.