Effects of natural pyrethrum and synthetic pyrethroids on the tiger mosquito,Aedes albopictus (skuse) and non-target flower-visiting insects in urban green areas of Padua,Italy

Abstract

The tiger mosquito is a key vector of several human diseases and is considered a public health concern worldwide. The implementation of strategies aimed at maximizing mosquito control without affecting non-target insect groups is of major importance. In a field trial, we tested the efficiency of a natural pyrethrum-based vs. a synthetic pyrethroid-based insecticide in reducing tiger mosquito population and how they affect the diversity of non-target flower-visiting insects in green urban areas. Only the pyrethroid insecticide was effective in reducing mosquito abundance, although its effects disappeared nine days after application. The two adulticides did not significantly affect the diversity of flower-visiting insects, probably because of their large body size and the difference in flying and foraging activity. To effectively control mosquito populations while preventing intoxication of non-target flower-visiting insects, adulticide applications should be applied early in the morning and only on bushes and trees. Results from our small-scale applications cannot be extrapolate when larger areas are treated.     

Population improvement in pyrethrum (Chrysanthemum cinerariaefolium Vis.)

Summary A population improvement programme in pyrethrum had progressively increased the mean pyrethrins content from 1.33 percent in the unselected base population to 1.97 percent in the population developed after one cycle of each of mass and recurrent selections. The selection had also increased the range of variation and the relative frequency of desirable plants.     

A new anthracnose disease of pyrethrum caused by Colletotrichum tanaceti sp. nov

A new pathogen of pyrethrum (Tanacetum cinerariifolium) causing anthracnose was described as Colletotrichum tanaceti based on morphological characteristics and a four‐gene phylogeny consisting of rDNA‐ITS, β‐tubulin (TUB2), glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and actin (ACT) gene sequences. The fungus produced perithecia in culture, requiring an opposite mating type isolate in a heterothallic manner. The initial infection strategy on pyrethrum leaves involved the formation of appressoria followed by production of multilobed infection vesicles in the epidermal cells. Infection and colonization then proceeded through thinner secondary hyphae, which resulted in the initial production of water‐soaked lesions followed by black necrotic lesions. The infection process was suggestive of a hemibiotrophic infection strategy. Moreover, phylogenetic analysis clearly showed that C. destructivum, C. higginsianum and C. panacicola were separate species that also had similar intracellular hemibiotrophic infection strategies as C. tanaceti, which all clustered in the C. destructivum complex. Colletotrichum spp. were detected at 1% incidence in seed of 1 of 19 seed lines, indicating the potential for seed as a source of inoculum into crops. Colletotrichum tanaceti was detected in leaf lesions from 11 of 24 pyrethrum fields surveyed between April and July 2012, at a frequency of 1·3–25·0% of lesions. Anthracnose probably contributes to the complex of foliar diseases reducing green leaf area in pyrethrum fields in Australia.     

Use of natural pyrethrum to control the red swamp crayfish Procambarus clarkii in a rural district of Italy

BACKGROUND: The crayfish Procambarus clarkii inflicts severe ecological and economic damages in Europe. To develop an efficient method for its control, four experiments were carried out to assess the impact of natural pyrethrum (i.e. Pyblast) on crayfish: (1) the 24 h LC₁₀₀ and LC₅₀ were quantified on crayfish; (2) the breakdown time of the 24 h LC₁₀₀ was assessed using Daphnia magna as a bioindicator; the effects of 24 h LC₁₀₀ on crayfish were investigated by applying the biocide into burrows (3) and in a drainage channel (4). RESULTS: Pyblast concentrations of 0.05 and 0.02 mg L^?1 corresponded to 24 h LC₁₀₀ and LC₅₀ respectively. The concentration of 0.05 mg L^?1 broke down after 72 h, whereas 0.02 mg L^?1 did not cause any significant mortality in D. magna after 24 h. However, 0.05 mg L^?1 had no effect on crayfish when introduced into the burrows, but led to a mortality of 95% when applied in the water. CONCLUSION: Experimental evidence is provided for the efficacy of Pyblast to control invasive crayfish. Obviously, before its use on a large scale, further studies are needed to find a concentration that will achieve the target 100% mortality with the shortest recovery time of the environment. Copyright © 2012 Society of Chemical Industry     

The effects of phytochemical pesticides on the growth of cultured invertebrate and vertebrate cells

A range of cultured cells of invertebrate and vertebrate origin was grown in the presence of a number of phytochemical pesticides to test the effect of the latter on cell proliferation. The main observation was that azadirachtin was a potent inhibitor of insect cell replication, with an EC50 of 1.5 x 10(10) M against Spodoptera cells and of 6.3 x 10(9) M against Aedes albopictus cells, whilst affecting mammalian cells only at high concentrations (> 10(-4) M). As expected, the other phytochemical pesticides, except for rotenone, had little effect on the growth of the cultured cells. Rotenone was highly effective in inhibiting the growth of insect cells (EC50:10(-8) M) but slightly less toxic towards mammalian cells (EC50:2 x 10(-7) M). Neem terpenoids other than azadirachtin and those very similar in structure significantly inhibited growth of the cell cultures, but to a lesser degree. The major neem seed terpenoids, nimbin and salannin, for example, inhibited insect cell growth by 23% and 15%, respectively.     

Botanical insecticides: for richer, for poorer

Botanical insecticides presently play only a minor role in insect pest management and crop protection; increasingly stringent regulatory requirements in many jurisdictions have prevented all but a handful of botanical products from reaching the marketplace in North America and Europe in the past 20 years. Nonetheless, the regulatory environment and public health needs are creating opportunities for the use of botanicals in industrialized countries in situations where human and animal health are foremost--for pest control in and around homes and gardens, in commercial kitchens and food storage facilities and on companion animals. Botanicals may also find favour in organic food production, both in the field and in controlled environments. In this review it is argued that the greatest benefits from botanicals might be achieved in developing countries, where human pesticide poisonings are most prevalent. Recent studies in Africa suggest that extracts of locally available plants can be effective as crop protectants, either used alone or in mixtures with conventional insecticides at reduced rates. These studies suggest that indigenous knowledge and traditional practice can make valuable contributions to domestic food production in countries where strict enforcement of pesticide regulations is impractical.     

饲料中拟除虫菊酯类农药的多残留分析技术

运用气相色谱仪建立了一种能同时检测饲料中8种拟除虫菊酯类农药(联苯菊酯、甲氰菊酯、三氟氯氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯、氟胺氰菊酯、溴氰菊酯)残留量的分析检测方法.饲料样品中的拟除虫菊酯类农药用丙酮提取,经石油醚萃取、弗罗里硅土柱净化后,用带微电子捕获检测器的气相色谱检测.结果表明,当添加质量浓度为0.05,0.2,0.5mg/kg时,方法的最小检出量为0.53×10-11～4.17×10-11g,添加回收率为74.19%～105.37%,变异系数为1.72%～11.19%,符合农药残留量检测的技术要求.     

Effect of Botanical Insecticides on the Foraging and Feeding Behavior of the Coccinellid PredatorCryptolaemus montrouzieri

To investigate the effect of botanicals on the foraging behavior of the mealybug predatorCryptolaemus montrouzieri Mulsant, predator larvae and adults were exposed to leaves and the mealybugPlanococcus citri (Risso) treated with one of the following: a crude neem seed extract; a formulation of azadirachtin (Azatin EC®); a pyrethrum extract; and one of two naphthoquinones isolated fromCalceolaria andina Benth. (BTG 504 and BTG 505). All the botanicals influenced the foraging behavior ofC. montrouzieri, at one or more concentrations. Larval and adult foraging behavior was influenced most by BTG 504 and neem also affected larval behavior; the predators contacted fewer treated leaves and spent less time on treated than on untreated leaves. Larvae also consumed fewer mealybugs treated with BTG 504 and BTG 505 compared with untreated mealybugs.     

The development of pyrethrum-based treatments against the ectoparasitic salmon lice Lepeophtheirus salmonis in sea cage rearing of atlantic salmon Salmo salar L.

Motile salmon lice Lepeophtheirus salmonis were successfully removed by an oil-based pyrethrum treatment mixture. The experiments described here are all based on skin exposure of the salmon Salmo salar L. The in-cage method, in which salmon would delouse themselves by jumping through a layer of treatment mixture, gave up to 86.9% delousing effect under low levels of solar radiation (October). However, at higher levels of radiation (May), the comparable effect decreased to 31.8%. Studies of exposure time vs. delousing effect showed no difference between 2-s and 10-s exposure and gave an overall delousing effect of 89.5%. Individual delousing procedures have thus been developed with a 4- to 6-s dip in the pyrethrum treatment mixture. A commercial method is described based on commercial Py-Sal 25 mixed with an anaesthetic bath before a vaccination or sorting operation. The overall delousing efficiency with this large-scale method was 85%. This is the method now used in commercial delousing with pyrethrum as the active component.     

真空冻干技术在除虫菊鲜花干燥中的应用研究

本文主要介绍了除虫菊鲜花的真空冷冻干燥技术的原理，条件和操作步骤。对气流干燥、远红外线（或烘箱)干燥、日光自然干燥及真空冷冻干燥四种干燥方法对除虫菊花的干燥条件、干花中水分含量和花中除虫菊素萃取进行了比较；还对真空冷冻干燥法工艺中影响除虫菊干燥后产品质量的温度及其升降速率、时间进行了探讨。该干燥技术具有干燥速率快、效率高、产品质量好的特点。冻干后的花中涂虫菊素萃取率达97．02％。干花中水分含量≤1．5％。