Search

Mistletoe is increasingly being reported as a horticultural pest, infecting many species grown commercially for fruit, nuts, and other food products. Unlike mistletoe impacts on forestry, the published research on mistletoe in horticulture is scant, with management guidelines reliant on anecdotes, un-replicated trials on unrelated species, and often in different countries and growing systems. We have integrated the existing work to summarize information on the most effective control strategies for mistletoe in horticulture, and call attention to the paucity of empirical research. Despite grower interest in growth regulators and herbicides, limited trials suggest chemical treatment of mistletoe is ineffective, consistent with findings from forestry and ornamental trees. Although labour-intensive, ongoing mechanical removal is the most effective strategy to minimize mistletoe impacts but, without information available on effects of mistletoe infection on yield or tree mortality, cost-effectiveness calculations are not possible. Given the range of herbivores that consume mistletoe tissues, biological control may be useful, both to prevent initial infection and also reduce impacts on infected hosts in commercial plantations. To catalyse more research on mistletoes in horticulture, we articulate six priorities for further work, emphasizing the utility of tree crops as model systems to address questions regarding mistletoe ecology and host-parasite dynamics more broadly. Key words: integrated pest management, plantation, orchard, host quality, monoculture. Le gui est de plus en plus victime de ceux qui le considerent comme un parasite en horticulture, contaminant de nombreuses especes cultivees commercialement pour les fruits, les noix et autres produits alimentaires. Contrairement aux impacts du gui en sylviculture, les recherches scientifiques publiees sur le gui en horticulture sont peu nombreuses, sa gestion reposant sur des anecdotes, des essais non repetes sur des especes sans rapport les unes avec les autres, souvent dans des pays et des modes de culture differents. Nous integrons les travaux existants afin de resumer les informations sur les meilleures strategies de lutte contre le gui en horticulture et soulignons la rarete des recherches empiriques. Malgre l'interet des producteurs pour les regulateurs de croissance et les herbicides, des essais limites suggerent que le traitement chimique du gui est inefficace, en concordance avec les resultats obtenus en foresterie et chez les arbres ornementaux. Bien qu'exigeant une importante main d'oeuvre, l'elimination mecanique en continu demeure la strategie la plus efficace pour minimiser l'impact du gui, mais sans la disponibilite d'informations sur les effets de l'infection par le gui sur le rendement ou la mortalite des arbres, les calculs du rapport cout-efficacite ne sont pas possibles. Compte tenu du spectre des herbivores qui consomment les tissus du gui, la lutte biologique pourrait etre utile afin de prevenir a la fois une infection initiale et pour reduire les impacts sur les hotes deja infectes dans des plantations commerciales. Afin de catalyser plus de recherches sur le gui en horticulture, nous formulons six priorites pour les travaux ulterieurs, soulignant l'utilite de cultures arboricoles comme systemes modeles pour aborder les questions concernant l'ecologie du gui et les dynamiques hote-parasite en general. [Traduit par la Redaction] Mots-cles : gestion integree des parasites, plantation, verger, qualite de l'hote, monoculture., Introduction Horticulture is a rapidly expanding industry, accounting for 35% and 39% of the total valueofcrops for the USA and Europe, respectively. In addition to accounting for an increasing proportion [...]

Mistletoes are considered keystone species on woodlands and savannas worldwide, providing a food resource for a diversified fauna, as well as a nutrient-enriched litter. Infections can be large (∼1–3 m) and, in some parts of the Amazonian savannas, parasitize up to 70% of hosts locally. Despite these facts, biomass of mistletoes is rarely investigated. Here we constructed allometric models to predict the biomass stock of the shrubby mistletoe Psittacanthus plagiophyllus in an Amazonian savanna. In addition, we determined whether host size could be used as a proxy for mistletoe biomass. Finally, we compared the biomass of mistletoes with that of trees, to evaluate their relative importance. We have shown that: (1) biomass of leaves (46.1% ± 13.5%) are as important as of stems (47.8% ± 13.5%), and relative contribution of stems increases as plant grows; (2) the model including width, breadth and vertical depth was the best (SE = 0.39, R2 = 0.9) for predicting individual mistletoe biomass; (3) mistletoe load and biomass per host had a positive, but weak (R2 = 0.11 and 0.09, respectively), relationship with host size, and thus such host information is a poor predictor of mistletoe biomass; and (4) in comparison with trees, mistletoes constituted less than 0.15% (0.5–22 kg ha−1) of the total above-ground biomass, suggesting that this life-form is irrelevant to the local biomass stock despite its unequivocal biological importance. [ABSTRACT FROM AUTHOR]

The article discusses the Psittacanthus, a species of the Mistletoes parasitic plant which is regarded hummingbird-pollinated and its other species such as the P. acinarius and P. eucalyptifolius to be bat and bee pollinated. It further discusses the flowering traits, the production of inflorescences and sugar concentration among these species.