Insecticides

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

The Department of Health and the Agency of Agriculture, Food & Markets continue to investigate the possible misuse of a pesticide in the Rutland region by AAA Accredited Pest Control company located on Cold River Road. The Agency of Agriculture summarily suspended the license of AAA Accredited Pest Control in July. The company is suspected of using a chemical (chlorpyrifos) to treat for bed bugs and other insects. Chlorpyrifos has been prohibited for indoor use by the U.S. Environmental Protection Agency since 2001. The state has obtained customer records from AAA from 2012 that show 150 residences, in addition to the 61 originally identified, that were sprayed with various pesticides. The state sent letters to those 150 residences on Aug. 7 asking permission to collect samples in homes for laboratory testing. The state is offering the testing at no cost. “We’re asking for everyone’s assistance and patience, and we are grateful to the residents who have had their homes tested so far,” said Health Commissioner Harry Chen, M.D. “We’ve been working closely with state and federal agencies and while the scope of our work has expanded, our approach is the same. We want to test the homes and then determine the best course of action to address any possible health concerns.”

Vor dem Hintergrund des bevorstehenden Verbots von Neonicotinoiden hat der Saatguthersteller DuPont Pioneer im Juni eine bundesweite Umfrage zum zukünftigen Rapsanbau durchgeführt. 528 Rapsbauern gaben ihre Einschätzungen zu den zukünftigen Herausforderungen im Rapsanbau. Angesichts der aktuellen Alternativlosigkeit der neonicotinoidhaltigen Insektizide beim Raps überrascht es, dass nur 16 Prozent der Landwirte angaben, den Rapsanbau in 2014 zu minimieren. 59 Prozent der Befragten wollen die bisherigen Raps-Anbaufläche beibehalten. 18 Prozent konnten noch keine Angaben dazu machen. Der Grund für die bleibend hohe Anbaubereitschaft liegt laut Ulrich Schmidt, Business Director von DuPont Pioneer, darin, dass "die Kultur für reine Ackerbaubetriebe alternativlos" ist.

Ladybirds are well known beneficial arthropods found in many habitats and ecosystems. They feed on various kinds of pest insects. In fact, coccinellids during their adult and larval stages attack on a variety of soft bodied herbivorous pests, including aphids, whiteflies, psyllids, and scales. Moreover they ingest fungal spores, pollen and nectar as complementary or even alternative foods when the preys are rare. In this study, the influence of sublethal concentrations (LC10 and LC30) of a neonicotinoid insecticide, thiamethoxam, was evaluated on life parameters of Hippodamia variegata Goeze (Coleoptera: Coccinellidae), Results showed that thiamethoxam changed life expectancy, and declined age-specific fecundity. The insecticide decreased preadult development time significantly, but it didn't have any effect on adult developmental period. Also, Eggs fecundity and fertility were not changed by treatments. According to this study, more care should be taken when thiamethoxam is used in IPM programs.

Recently, legislative decisions withdrew or temporarily suspended the use of neonicotinoids and fipronil as seeds tanning in many countries because of their endocrine-disrupting activity imputable to the bees’ toxicity. In this study, the occurrence of acetamiprid, fipronil, clothianidin, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam was detected in 66 samples of commercial treated corn seeds, collected in the Italian market in the frame of ministerial institutional quality control activity. Because of the lack of a validated analytical protocol for neonicotinoid detection in seeds, a routinely suitable liquid chromatography–tandem mass spectroscopy (LC-MS/MS) analytical method was developed and statistically validated on fortified corn seeds. Survey results demonstrated that 88% of the investigated seed samples showed the presence of residues of clothianidin, fipronil, thiamethoxam and thiacloprid, either individually or simultaneously, with values that ranged from about 0.002 to 20 mg kg−1, which evidenced the alarming illicit use of these pesticides in seed treatments.

Chemical suppression of arthropod herbivores is the most common approach to plant protection. Insecticides, however, can cause unintended, adverse consequences for non-target organisms. Previous studies focused on the effects of pesticides on target and non-target pests, predatory arthropods, and concomitant ecological disruptions. Little research, however, has focused on the direct effects of insecticides on plants. Here we demonstrate that applications of neonicotinoid insecticides, one of the most important insecticide classes worldwide, suppress expression of important plant defense genes, alter levels of phytohormones involved in plant defense, and decrease plant resistance to unsusceptible herbivores, spider mites Tetranychus urticae (Acari: Tetranychidae), in multiple, distantly related crop plants. Using cotton (Gossypium hirsutum), corn (Zea mays) and tomato (Solanum lycopersicum) plants, we show that transcription of phenylalanine amonia lyase, coenzyme A ligase, trypsin protease inhibitor and chitinase are suppressed and concentrations of the phytohormone OPDA and salicylic acid were altered by neonicotinoid insecticides. Consequently, the population growth of spider mites increased from 30% to over 100% on neonicotinoid-treated plants in the greenhouse and by nearly 200% in the field experiment.

Charttechnischer Ausblick 07.08.13: Das sieht nicht mehr wirklich gesund aus. Tagelang schon kämpft SYNGENTA im Tageschart um eine Bodenbildung um 370 CHF, der Kampf endet scheinbar zugunsten der Bären. Noch liegt um 366 CHF ein letzter seidener Faden, darunter muss man sich aber sofort in Richtung 350 CHF orientieren. Wohingegen ab 375 CHF die Bullen zurück im Spiel wären, mit Ziel 395 CHF dann. Letztes Update 02.07.13: Das bemerkenswerte am heutigen Kaufsignal im Tageschart von SYNGENTA ist der Umstand, dass es weit und breit das einzige seiner Sorte ist. Während sich andernorts aber nur bearische Fortsetzungsmuster zeigen, bricht diese Aktie heute über sein noch junges Zwischenhoch und peilt damit das nächste Kursziel von 390 CHF an. Enttäuschend wäre hingegen ein Rückfall unter 365, in diesem Fall rechnen wir mit einem sofortigen Rutsch in Richtung 350 CHF.

Der Deutsche Berufs- und Erwerbsimkerbund (DBIB) und der Bund für Umwelt und Naturschutz Deutschland (BUND) appellieren an die deutschen Landwirte, bei der anstehenden Raps-Aussaat freiwillig auf Pestizide zu verzichten, die zur Gruppe der Neonikotinoide gehören. Diese vor allem für Bienen gefährlichen Nervengifte werden zum Beizen des Saatgutes eingesetzt und sind nach Erkenntnissen von Toxikologen 6000 bis 7000mal giftiger als DDT. Untersuchungen ergaben, dass Neonikotinoide bei Bienen und Vögeln zu Einschränkungen der Orientierungsfähigkeit und zu Störungen des Immunsystems führen können. Außerdem töten diese Pestizide viele Insektenarten, die Vögeln als Nahrung dienten. Die EU-Mitgliedsstaaten hatten im April dieses Jahres beschlossen, ab 1. Dezember die drei gefährlichsten Neonikotinoide zunächst für zwei Jahre vom Markt zu verbannen. Betroffen von diesem Teilverbot sind die Wirkstoffe Clothianidin, Imidacloprid sowie Thiamethoxam. „Neonikotinoide sind für das Bienensterben und das Verschwinden von Vögeln in landwirtschaftlich geprägten Regionen mit verantwortlich. Wenn bei der Raps-Aussaat jetzt auf diese Agrargifte verzichtet wird, dann könnten sich Bienen- und Vögelpopulationen langsam wieder erholen“, sagte der BUND-Vorsitzende Hubert Weiger.

Field and tunnel cage studies were undertaken to determine the extent to which honey bees foraging on citrus blossoms were exposed to imidacloprid and its metabolites when citrus trees were treated with soil applications of the insecticide. Imidacloprid, imidacloprid olefin and 5-hydroxy imidacloprid were detected in nectar and pollen sampled from the flowers of citrus trees treated with imidacloprid up to 232 days prior to bloom. In tunnel studies, where foraging was restricted exclusively to citrus, imidacloprid residues in nectar extracted from flowers and from bee crops were similar (<10 ng mL−1); the residue levels were about threefold higher in nectar sampled from comb. Concentrations of imidacloprid in nectar were higher in trees treated with higher application rates.