Tag Archives: Pieris brassicae

406-411 L. Metspalu, K. Hiiesaar, K. Jõgar, E. Švilponis, A. Ploomi, I. Kivimägi,A. Luik and N. Mens’hikova
Oviposition preference of Pieris brassicae (L) on different Brassica oleracea var. capitata L. cultivars
Abstract |

Oviposition preference of Pieris brassicae (L) on different Brassica oleracea var. capitata L. cultivars

L. Metspalu, K. Hiiesaar, K. Jõgar, E. Švilponis, A. Ploomi, I. Kivimägi,A. Luik and N. Mens’hikova

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,
¹ Kreuzwaldi St, 51014, Tartu; e-mail: Luule.Metspalu@emu.ee

Abstract:

Abstract Cabbage White Butterfly, Pieris brassicae L. is widely distributed pest world wide and causes severe damage to white cabbage (Brassica oleracea var. capitata f. alba L.). We studied oviposition preference of P. brassicae on six different cabbage cultivars in the field experiment. As in Estonia farmers grow rather numerous cabbage cultivars, the determination of more resistant cabbage cultivars is of great importance for farmers. Significantly more eggs were laid on the late cultivars ‘Krautkaizer’ (52% of all of the counted eggs) and ‘Turquoise’ (40%). The mid season cultivars ‘Krautman’, and ‘Lennox’ were chosen more or less to the same extent (2.5–5%). P. brassicae adults avoid the early cultivars ‘Parel’ and ‘Golden Acre’.

Key words:

, ,




203-210 K. Jõgar, A. Kuusik, L. Metspalu, K. Hiiesaar, A. Luik and M. Grishakova
Results of treatments with natural insecticidal substances on the development and physiological state of insects
Abstract |
Full text PDF (286 kB)

Results of treatments with natural insecticidal substances on the development and physiological state of insects

K. Jõgar, A. Kuusik, L. Metspalu, K. Hiiesaar, A. Luik and M. Grishakova

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,64 Kreutzwaldi St., 51014 Tartu, Estonia; e-mail: katrin.jogar@emu.ee

Abstract:

Reviewed are the results of treatments carried out in the Institute of Agricultural and Environmental Sciences of treatments with natural insecticidal substances on the development and physiological state of insects, using neurotoxical plant extracts (pyrethrins), plant extracts possessing several modes of action (neem) and an Insect Growth Regulator (extract of Ledum palustre possessing properties of juvenile hormone). Physiological changes evoked with treatments were monitored by means of complex methods including a constant volume respirometer, infrared actograph, infrared gas analyzer (IRGA),and a microcalorimeter.Diapausing lepidopterous pupae (Pieris brassicae, Mamestra brassicae) exhibiteddiscontinuous gas exchange cycles (DGCs). After treatments of the pupae of P. brassicae with neem, the DGCs were abolished, suggesting direct action on the neuromuscular system. The disappearance of DGCs was accompanied with lethal desiccation, supporting the hypothesis that DGC is an adaptation for restricting the respiratory water losses. Cyclic gas exchange was also lost after treatments with neem in adults of Leptinotarsa decemlineata. The clear gas exchange cycles in the pupae of Galleria mellonella, Tenebrio molitor and P. brassicae were also abolished after treatments with extracts of Artemisia vulgaris, Tanacetum vulgare, T. roseum and L. palustre. The timing of the normal and failed ecdysis (after treatment with L. palustre) as well as length of intercdysial periods in T. molitor pupae was measured exactly from calorimetric recordings. The treated pharate pupae transformed into extra-pupal instars, which is a symptom of juvenilizing effect.

Key words:

, , , , , ,




21–37 K. Jõgar, L. Metspalu, K. Hiiesaar, A. Luik, A.-J. Martin, M. Mänd, R. Jaaniso and A. Kuusik
Physiology of diapause in pupae of Pieris brassicae L. (Lepidoptera: Pieridae)
Abstract |
Full text PDF (420 kB)

Physiology of diapause in pupae of Pieris brassicae L. (Lepidoptera: Pieridae)

K. Jõgar¹, L. Metspalu¹, K. Hiiesaar¹, A. Luik¹, A.-J. Martin¹, M. Mänd¹, R. Jaaniso² and A. Kuusik¹

¹Institute of Agricultural and Enviromental Sciences, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: katrinj@eau.ee
²Institute of Physics University of Tartu, Riia 142, 51014 Tartu, Estonia

Abstract:

Respiration patterns, water loss and heart activity were investigated during the first three months of diapause in non-acclimated pupae of Pieris brassicae. To observe and record diverse events during pupal diapause, a complex apparatus was used: a micro-calorimeter, an electrolytic respirometer, a fibre-optical oxygen sensor, a flow-through respirometer (infrared gas analyzer), an infra-red actograph and a thermocouple cardiograph. Most of the pupae (about 80%) reared in 2004 were characterised as long-cycle individuals whose discontinuous gas exchange cycles (DGCs) were very regular and lasted 26 hours on average. The remainder of the pupae studied were short-cycle individuals displaying irregular DGCs lasting less than 2 hours. Standard metabolic rates (SMR) measured during the first month of diapause between long- and short-cycle pupae did no differ significantly, being about 0.018 ml O2 g-1 h-1. At the same time, water loss rate (WLR) in long- and short-cycle pupae differed significantly, being 1.07 and 1.61 mg g-1 day-1, respectively. During the first three months of diapause, the values of SMR and WLR did not change significally in the long-cycle pupae. In the short-cycle individuals, SMR and WLR thereupon increased gradually during the months, but the values of SMR never reached the levels characteristic of pharate adult development. The heartbeat reversal was characteristic for both the long- and short-cycle individuals but heart pauses in the first pupal group were regular, lasting 20–30 min, whereas in the second group the heart pauses were shorter and irregular.
From the results we concluded that the intensity of pupal diapause varied individually despite the apparently similar developmental conditions of the individuals, however, some hidden factors were obviously involved in diapause induction. The primary cause of the enhanced water loss in the short-cycle pupae was obviously the disturbing of the water conserving mechanisms due to the irregular gas exchange.

Key words:

, , , , , , ,




211–220 L. Metspalu, K. Hiiesaar and K. Jõgar
Plants influencing the behaviour of Large White Butterfly (Pieris brassicae L.)
Abstract |
Full text PDF (112 kB)

Plants influencing the behaviour of Large White Butterfly (Pieris brassicae L.)

L. Metspalu, K. Hiiesaar and K. Jõgar

Abstract:

Large White Butterfly, Pieris brassicae L. (LWB) is one of the greatest pests of cruciferous cultures in Estonia, and, in the years of its biggest abundance, it can destroy a significant part of a crop.  Many plants contain natural compounds that can repel and/or attract insects and protect neighbouring plants. This principle is used in a method known as companion planting. The aim of this paper was to establish to what extent it was possible to influence, by using companion plants, the oviposition intensity of adults of LWB on Brassica oleracea var. capitata f. alba.  Cabbage plots were surrounded, as a border around garden beds, by the following plant species: Salvia horminum L. (syn. viridis L), Chrysanthemum carinatum Schousboe, Tagetes patula L., Allium cepa L. or Calendula officinalis L. Companion plants were replanted on the experimental plots in two rows. On control plots only cabbage was growing.
French marigold, T. patula and painted daisy, C. carinatum were oviposition repellent to P. brassicae – compared with the control variant; butterflies laid fewer eggs on cabbage of these variants. At the same time, flowers of T. patula were attractive to adults of P. brassicae as the butterfly fed intensively on the flowers. There were no butterflies on flowers of C. carinatum, allowing us to conclude that this plant was a repellent to adults of P. brassicae. Certain repellent effects of  painted sage, S. horminum,  appeared towards the end of the summer, when the plants were in full flower. Butterflies laid eagerly eggs on cabbage plants surrounded by calendula, C. officinalis and onion, A. cepa. Our experiments showed how important it is to reckon with a certain pest, the control of which is intended, in choosing plants for founding a garden with diverse vegetation.

Key words:

, ,




85–92 L. Metspalu1, K. Hiiesaar1, J. Jõudu2 and A. Kuusik1
Influence of food on the growth, development and hibernation of Large White Butterfly (Pieris brassicae)
Abstract |
Full text PDF (218 kB)

Influence of food on the growth, development and hibernation of Large White Butterfly (Pieris brassicae)

L. Metspalu1, K. Hiiesaar1, J. Jõudu2 and A. Kuusik1

1Institute of Plant Protection, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: mluule@eau.ee
2Department of Field Crop Husbandry, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia

Abstract:

The abundance of Large White Butterfly (LWB), Pieris brassicae fluctuates from year to year, and a peak in the population is reached in every five to seven years, after which there occurs an abrupt decrease in the abundance. The natural checks of the population are primarily weather, parasitoids and pathogens, but the quality of food is also an important factor. The criteria for estimating the influence of food were the duration of caterpillar stage, the mortality rate of caterpillars and prepupae, the weight of pupae and the winter mortality of diapausing pupae. Foodplants: Brassica oleracea var. capitata f. alba, B. oleracea var. capitata f. rubra, B. oleracea var. gemmifera, B. oleracea var. botrytis, B. oleracea var. acephala, B. napus var. napobrassica, Tropaeolum majus, Armoracia rusticana.
In our experiments, the most unsuitable foodplants for larvae were Tropaeolum majus and Armoracia rusticana. There appeared a high mortality rate among caterpillars feeding on both of them as well as among their hibernating pupae. It can be concluded that one of the reasons for the remarkable decrease in the pest population following the massive reproduction of LWB is the high mortality rate of caterpillars growing on less valuable foodplants. The pupae are underweight and, in most cases, they perish during winter.

Key words:

, , , , ,