Ximena Cibils Stewart

National Institute of Agricultural Research of Uruguay · Pastures and Forages

Purpose Silicon (Si) accumulation by grasses alleviates diverse biotic and abiotic stresses. Despite this important functional role, we have limited understanding of how root microbial symbionts, such as arbuscular mycorrhizal (AM) fungi, affect Si uptake and even less about how Si supply and accumulation affect AM fungal colonisation. Our objectiv...

Predicting how plants allocate to different anti-herbivore defences in response to elevated carbon dioxide (CO2) concentrations is important for understanding future patterns of crop susceptibility to herbivory. Theories of defence allocation, especially in the context of environmental change, largely overlook the role of silicon (Si), despite it b...

Aphids that attack canola (Brassica napus L.) exhibit feeding preferences for different parts of canola plants, which may be associated with brassica-specific glucosinolates. However, this idea remains untested. Furthermore, canola aphid species employ different strategies for tolerating glucosinolates. While the green peach aphid, Myzus persicae (...

Grasses have developed a wide range of morphological and physiological mechanisms to resist herbivory. For instance, they accumulate silicon (Si) in tissue, as physical defence, and associate symbiotically with foliar Epichloë‐endophytes that provide chemical defence via antiherbivore alkaloids. Recent evidence showed that some Epichloë‐endophytes...

Exotic water primroses are aggressive invaders in both aquatic and riparian ecosystems worldwide. Water primrose [Ludwigia hexapetala (Hook. & Arn.) Zardini, Gu & P. H. Raven], floating primrose-willow [Ludwigia peploides (Kunth) P. H. Raven subsp. peploides], floating primrose-willow [Ludwigia peploides (Kunth) P. H. Raven subsp. montevidensis (Sp...

Silicon (Si) accumulation alleviates a diverse array of environmental stresses in many plants, including conferring physical resistance against insect herbivores. It has been hypothesised that grasses, in particular, utilise ‘low metabolic cost’ Si for structural and defensive roles under nutrient limitation. While carbon (C) concentrations often n...

Silicon (Si) can adversely affect insect herbivores, particularly in plants that evolved the ability to accumulate large quantities of Si. Very rapid herbivore‐induced accumulation of Si has recently been demonstrated, but the level of protection against herbivory this affords plants remains unknown. Brachypodium distachyon, a model Si hyperaccumul...

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of t...

Altered precipitation patterns due to climate change are likely to impose water‐deficit stress in plants resulting in changes to specific leaf mass, leaf water content and chemical defences that may impact herbivorous arthropods. Grasses, in particular, accumulate large concentrations of silicon (Si) which provides physical defence against herbivor...

Silicon (Si) has an important role in mitigating diverse biotic and abiotic stresses in plants, mainly via the silicification of plant tissues. Environmental changes such as atmospheric CO2 concentrations may affect grass Si concentrations which, in turn, can alter herbivore performance. We recently demonstrated that pre‐industrial atmospheric CO2...

This chapter presents an overview of the interactions between plant roots and root-feeding insect herbivores, focussing on changes in growth and physiology and crucially how roots are defended against insect attack. Several reviews have covered the ecology and management of insect root herbivores, together with their interactions with the abiotic a...

fao has proclaimed 2020 as the “International Year of Plant Health”. In this context, the present review aims to synthesize the rich history of pest management in Uruguay. To our knowledge, this effort is unprecedented. To accomplish this, the development of pest management methods was compiled from the second half of the 19th century to the presen...

Cool season grasses associate asymptomatically with foliar Epichloë endophytic fungi in a symbiosis where Epichloë spp. protects the plant from a number of biotic and abiotic stresses. Furthermore, many grass species can accumulate large quantities of silicon (Si), which also alleviates a similar range of stresses. While Epichloë endophytes may imp...

Silicon (Si) has been widely reported to improve plant resistance to water stress via various mechanisms including cuticular Si deposition to reduce leaf transpiration. However, there is limited understanding of the effects of Si on stomatal physiology, including the underlying mechanisms and implications for resistance to water stress. We grew tal...

el conocimiento de la biología de las isocas es una herramienta de gran valor para evitar o atender a tiempo los problemas causados por estos insectos en pasturas y cultivos. el presente artículo aborda en forma ilustrativa los principales aspectos de su biología, daños y manejos agronómicos recomendados. Foto: Lucía Meneses • Isoca es el nombre vu...

This book contains 32 chapters focusing on the biological control of many invasive pests, diseases and weeds and ensuring a healthy and sustainable food supply in various countries in Latin America and the Caribbean. The rich history of biological control in the region is documented and steps for the future success of the biological control of inva...

The green peach aphid (GPA), Myzus persicae S., and the cabbage aphid (CA), Brevicoryne brassicae L., exhibit a feeding preference when exposed to different canola (Brassica napus L.) plant structures. Preference may be associated with the concentration and/or composition of allelochemicals; specifically, glucosinolates (GLS). Furthermore, each aph...

Cyrtobagous salviniae is widely used in several countries including the United States, South Africa and Australia for biological control of Salvinia molesta Mitchell (Salviniales: Salviniaceae). Despite considerable success in tropical and subtropical regions, the effectiveness of C. salviniae on S. molesta is inconsistent in temperate regions, ind...

Winter canola production in the south-central US is threatened by a complex of different aphid species, including Brevicoryne brassicae (cabbage aphid). Colonizing behavior of these aphids may be affected by intrinsic characteristics of the host plant including nutritional quality, secondary compounds, plant architecture or feeding structure. Under...

Several species of bumble bees are declining in the United States; these declining populations often show higher prevalence of Nosema bombi, a microsporidian pathogen. To date, surveys of bumble bee pathogens in the United States have only been conducted on workers and males, yet the health of a population is ultimately dependent on the success of...

In the absence of aphid migration events, lady beetles are capable of suppressing soybean aphid populations below economic injury levels in much of the North Central US. Several factors may influence their ability to locate suitable prey patches, including abiotic factors like wind direction or speed, or biotic factors like prey availability, locat...

We examined inheritance of resistance, feeding behavior, and fitness costs for a laboratory-selected strain of western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), with resistance to maize (Zea maize L.) producing the Bacillus thuringiensis Berliner (Bt) toxin Cry3Bb1. The resistant strain developed faster and...

The cabbage aphid (Brevicoryne brassicae) is a perennial pest that specializes on plants of the Brassicaceae family. Feeding damage observed in winter canola (Brassica napus) can result in seedling death, curling, yellowing, stunting, or virus transmission; all of which can alter seed quality and reduce yield up to 33%. The cabbage aphid attacks ca...

Squash vine borer (Melittia cucurbitae), squash bug (Anasa tristis), and striped cucumber beetle (Acalymma vittatum) cause substantial economic losses on several cucurbit crops. Timing of insecticide sprays, deployment of row covers, and other management practices are likely to be more effective if they correspond to the timing of arrival of these...