Adventitious rooting of Chrysanthemum is stimulated by a low red:far-red ratio.

Adventitious rooting, a critical process in the vegetative propagation of many ornamentals, can be affected by both light intensity and light quality. We investigated the use of spectral light quality to improve adventitious rooting of Chrysanthemum morifolium cuttings by applying different combinations of blue, red and far-red light. Additionally, unrooted cuttings were treated before planting with two auxin transport inhibitors (TIBA and NPA) to study the effect of light quality on auxin biosynthesis and/or transport.

Heritability of symbiont density reveals distinct regulatory mechanisms in a tripartite symbiosis.

Beneficial eukaryotic-bacterial partnerships are integral to animal and plant evolution. Understanding the density regulation mechanisms behind bacterial symbiosis is essential to elucidating the functional balance between hosts and symbionts. Citrus mealybugs, Planococcus citri (Risso), present an excellent model system for investigating the mechanisms of symbiont density regulation.

Suboptimal Light Conditions Influence Source-Sink Metabolism during Flowering.

Reliance on carbohydrates during flower forcing was investigated in one early and one late flowering cultivar of azalea (Rhododendron simsii hybrids). Carbohydrate accumulation, invertase activity, and expression of a purported sucrose synthase gene (RsSUS) was monitored during flower forcing under suboptimal (natural) and optimal (supplemental light) light conditions, after a cold treatment (7°C + dark) to break flower bud dormancy. Post-production sucrose metabolism and flowering quality was also assessed.

Diurnal temperature variations affect development of a herbivorous arthropod pest and its predators.

The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen's inequality.

Supplemental food for Amblyseius swirskii in the control of thrips: feeding friend or foe?

Background: In integrated pest management systems in greenhouse crops, the predatory mite Amblyseius swirskii is becoming increasingly important as a biological control agent of various pests, especially thrips and whiteflies. An emerging strategy to promote the predator's establishment and retention in the crop consists in providing food supplements. However, when faced with omnivorous pests, such as the western flower thrips, Frankliniella occidentalis, food supplements need to be applied with extreme care, in order not to boost population growth of the pest.

Alternating temperatures affect life table parameters of Phytoseiulus persimilis, Neoseiulus californicus (Acari: Phytoseiidae) and their prey Tetranychus urticae (Acari: Tetranychidae).

Increasing energy costs force glasshouse growers to switch to energy saving strategies. In the temperature integration approach, considerable daily temperature variations are allowed, which not only have an important influence on plant growth but also on the development rate of arthropods in the crop. Therefore, we examined the influence of two constant temperature regimes (15 °C/15 °C and 20 °C/20 °C) and one alternating temperature regime (20 °C/5 °C, with an average of 15 °C) on life table parameters of Phytoseiulus persimilis and Neoseiulus californicus and their target pest, the two-spotted spider mite Tetranychus urticae at a 16:8 (L:D) h photoperiod and 65 ± 5 % RH.

Efficacy results of insecticides against Cydia pomonella, the codling moth, in Belgium during the last decade (1998-2007).

The codling moth is an economically important top fruit pest, with its major flight from May till August. We give an overview of ten years of results of efficacy field trials against the codling moth Cydia pomonella, with a number of commonly used products (diflubenzuron, fenoxycarb, flufenoxuron, indoxacarb, granulosis virus, methoxyfenozide and tebufenozide). All trials were executed according to EPPO guidelines.

The importance of arthropod pests in Belgian pome fruit orchards.

Located in temperate, maritime climate with frequent rainfall, crop protection in Belgian orchards is dominated by fungicides. Though, the importance of arthropod pests should not be underestimated. Pcfruit, the former Research station of Gorsem, has been maintaining a warning system for fruit pests in Belgium since 1944.

Sublethal effects of crop protection on honey bee pollination: foraging behaviour and flower visits.

Crop protection strategies essential for pest and disease control can pose risk to pollinators. Fruits cannot be grown commercially without the use of crop protection agents, either from organic or chemical origin. The use of products with toxic effects is banned during flowering, and precise pre-flowering intervals have to be respected in Good Agricultural Practice.

Acaricides and predatory mites against the begonia mite, Polyphagotarsonemus latus (Acari: Tarsonemidae), on Hedera helix.

In recent years, the begonia mite (Polyphagotarsonemus lotus) has become an important threat to different ornamental cultures in warm greenhouses. At present there are no professional plant protection products registered in Belgium for the control of mites of the Tarsonemidae family. In a screening trial, we evaluated the efficacy of a range of different acaricides: abamectin, milbemectin, pyridaben, spirodiclofen.

Degeneration of sperm reservoir and the loss of mating ability in worker ants.

Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term storage of sperm. Such 'non-sexual' workers are restricted to laying unfertilized eggs that give rise to males, and they cannot compete with the queens for the production of female offspring. In sharp contrast, workers in 200-300 species from phylogenetically basal subfamilies can reproduce sexually ('gamergates') because they retain a functional spermatheca like the queens.

Queen-worker differences in spermatheca reservoir of phylogenetically basal ants.

Ant queens mate when young and store sperm in their spermatheca to fertilize eggs for several years until their death. In contrast, workers in most species never mate. We have compared the histological organization of spermathecae in 25 poneromorph species exhibiting various degrees of queen-worker dimorphism.

Sumo wrestling in ants: major workers fight over male production in Acanthomyrmex ferox.

In the myrmicine ant Acanthomyrmex ferox, major workers have the same number of ovarioles as queens, thrice that of minor workers, making them well suited for egg-laying. In the queen's presence, infrequent aggression allows ranking of majors but they lay only unviable trophic eggs. Major workers engage each other, but not the minors, in antennal boxing and spectacular shaking contests, a novel interaction in ants.

The energetic cost of reproductive conflicts in the ant Pachycondyla obscuricornis.

In a variety of social animals, individuals can secure reproductive rights through aggressive dominance. Direct individual benefits of aggression are widely recognized, but underlying costs affecting group productivity, and thus indirect benefits, are less clear. Costs of aggressive regulation of reproduction are especially important in small social insect colonies, where individual workers could potentially dominate male production.

Comparative survey of abdominal gland secretions of the ant subfamily Ponerinae.

The chemical contents of three abdominal glands were investigated in representative species of the ponerine ants. The Dufour glands of 14 species show a wide variety of contents. In Mystrium camillae and Proceratium itoi, no volatile substances were found in either the Dufour or venom glands.