Fertilization with beneficial microorganisms decreases tomato defenses against insect pests

International audienceThe adverse effects of chemical fertilizers on agricultural fields and the environment are compelling society to move toward more sustainable farming techniques. “Effective microorganisms” is a beneficial microbial mixture that has been developed to improve soil quality and crop yield while simultaneously dramatically reducing organic chemical application. Additional indirect benefits of beneficial microorganisms application may include increased plant resistance to herbivore attack, though this has never been tested till now. Tomato plants were grown in controlled greenhouse conditions in a full-factorial design with beneficial microorganisms inoculation and commercial chemical fertilizer application as main factors. We measured plant yield and growth parameters, as well as resistance against the generalist pest Spodoptera littoralis moth larval attack. Additionally, we measured plant defensive chemistry to underpin resistance mechanisms. Overall, we found that, comparable to chemical fertilizer, beneficial microorganisms increased plant growth fruit production by 35 and 61 %, respectively. Contrary to expectations, plants inoculated with beneficial microorganisms sustained 25 % higher insect survival and larvae were in average 41 % heavier than on unfertilized plants. We explain these results by showing that beneficial microorganism-inoculated plants were impaired in the induction of the toxic glycoalkaloid molecule tomatine and the defense-related phytohormone jasmonic acid after herbivore attack. For the first time, we therefore show that biofertilizer application might endure unintended, pest-mediated negative effects, and we thus suggest that biofertilizer companies should incorporate protection attributes in their studies prior to commercialization

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Comportamento de larvas de Diabrotica speciosa (Coleoptera: Chrysomelidae) em resposta ao CO2 e a plântulas de espécies cultivadas Behavioral responses of Diabrotica speciosa (Coleoptera: Chrysomelidae) larvae to CO2 and seedlings of host plants

As respostas de larvas de Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) ao CO2 e o comportamento destas larvas quando expostas a plantas hospedeiras e não hospedeiras foram estudadas em laboratório. Larvas de primeiro ínstar de D. speciosa foram utilizadas. Num primeiro bioensaio, as larvas preferiram o tratamento com CO2, que foi gerado a partir da reação de bicarbonato de potássio com ácido acético em oposição a água destilada. Quando se observou o comportamento das larvas em relação a plantas hospedeiras, verificou-se que ocorreu um número significativamente maior de "mudanças de direção" em milho e milho pipoca do que em feijão, soja, trigo e sorgo. Este parâmetro foi inferior no sorgo em relação a todos os outros tratamentos. Valores similares foram verificados em milho pipoca e milho (26,2 e 24,2, respectivamente). Em relação a distância percorrida, foram verificadas maiores distâncias na aveia em comparação com milho pipoca, milho, feijão e sorgo. Após o contato das larvas com sorgo, elas não apresentaram comportamento de busca, pois a larva caía da plântula ou não se movia .<br>Responses of Diabrotica speciosa (Germar) (Coleoptera: Chrysomelidae) larvae to CO2 and their behavior when exposed to host and non host plants were studied in the laboratory. First instar larvae of D. speciosa were used. In a first bioassay, larvae preferred the treatment with CO2, from the reaction of the potassium bicarbonate and acetic acid, in opposition to distillated water. When the behavior of the larvae was observed in response to host plants, a significant higher number of turns was found in corn and popcorn than in common beans, soybean, wheat and sorghum. Sorghum differed from all other treatments with a lower number of turns. Similar values were found in popcorn and corn. The greater distances ranged were found on oats in comparison to pop corn, corn, common beans and sorghum. After contact with sorghum seedlings larvae did not present searching behavior because they fell from the seedling or no movements were saw seen

Repellent, antifeedant and insecticidal effects of neem oil on Microtheca punctigera

The effects of concentrations (0.00, 0.25, 0.50 and 1.00%) of the neem tree (Azadirachta indica - Meliaceae) oil emulsion on the behavioral and biological parameters of M. punctigera were investigated in the laboratory. Wild radish (Raphanus raphanistrum L.) host plant was used. Multiple and no-choice feeding preference assays were conducted which shown multiple effects. The males were repelled by the neem oil in multiple-choice assay. The adult (multiple-choice) and larvae (multiple and no-choice) feeding were deterred. The larvae mortality was higher in the neem oil treated than the control leaves. Further investigations are suggested to test neem oil in the management of the pest in the field.<br>Besouros Microtheca punctigera (Achard) são pragas sérias de plantas hospedeiras da família Brassicaceae. Efeitos das concentrações (0,00; 0,25; 0,50; e 1,00%) do óleo emulsionável de nim (Azadirachta indica Meliaceae) sobre parâmetros de comportamento e biologia de M. punctigera foram investigados em laboratório. Nabiça (Raphanus raphanistrum L.) foi a planta hospedeira utilizada. Ensaios de preferência alimentar com múltipla e sem chance de escolha foram conduzidos. Múltiplos efeitos do óleo de nim foram observados. Machos foram repelidos pelo óleo de nim em teste de múltipla escolha. Adultos (múltipla escolha) e larvas (múltipla e sem chance de escolha) sofreram deterrência. A mortalidade de larvas foi mais elevada nos tratamentos com óleo de nim que no tratamento controle. Futuras investigações são sugeridas para testar o óleo de nim no manejo de pragas no campo