120 resultados para avocado pest
Resumo:
Will the Convention on Biological Diversity put an end to biological control? Under the Convention on Biological Diversity countries have sovereign rights over their genetic resources. Agreements governing the access to these resources and the sharing of the benefits arising from their use need to be established between involved parties. This also applies to species collected for potential use in biological control. Recent applications of access and benefit sharing principles have already made it difficult or impossible to collect and export natural enemies for biological control research in several countries. If such an approach is widely applied it would impede this very successful and environmentally safe pest management method based on the use of biological diversity. The International Organization for Biological Control of Noxious Animals and Plants has, therefore, created the "Commission on Biological Control and Access and Benefit Sharing". This commission is carrying out national and international activities to make clear how a benefit sharing regime might seriously frustrate the future of biological control. In addition, the IOBC Commission members published information on current regulations and perceptions concerning exploration for natural enemies and drafted some 30 case studies selected to illustrate a variety of points relevant to access and benefit sharing. In this article, we summarize our concern about the effects of access and benefit sharing systems on the future of biological control.
Resumo:
Survey of ear flies (Diptera, Ulidiidae) in maize (Zea mays L.) and a new record of Euxesta mazorca Steyskalin Brazil. Species of Euxesta (Diptera, Ulidiidae), known as silk flies or ear flies, are becoming increasingly important as maize insect pests in South America, although very little is known about them in Brazil. The larvae of some species of this genus initially damage female reproductive tissues, and then the developing kernels on the ear. As a result of feeding, fermentation and associated odors cause complete loss of the grain because it is no longer fit for human or livestock consumption. The main objective of this work was to evaluate the incidence of Euxesta spp. in Brazilian maize fields and to determine the most prevalent species using two different hydrolyzed protein foods attractants, BioAnastrepha® (hydrolyzed maize protein) and Torula, placed inside McPhail traps. The two species identified were E. eluta Loew and E. mazorca Steyskal, the latter being a new record from Brazil. Between the two species, E. eluta was the more abundant in maize fields. Both attractants were efficient in capturing the two species. However, BioAnastrepha® captured significantly more insects than Torula.
Resumo:
Toxic effects of essential plant oils in adult Sitophilus oryzae (Linnaeus) (Coleoptera, Curculionidae). Stored grains are subject to losses in quality nutritional value and in sanitation from the time they are stored to the time they are consumed. Botanical insecticides may offer an alternative solution for pest control. The objective was to test the insecticidal properties of the essential oils of Cymbopogon citratus (leaf), Zingiber officinale (root) and Mentha sp. (leaf). The efficacy of these oils was tested to control the rice weevil, S. oryzae, using hydrodistillation. Chemical analysis of the essential oils was carried out by gas chromatography. Major components of C. citratus were geranial (48%) and neral (31%), of Z. officinale were α-zingibereno (13%), geranial (16%), neral (10%) and α-farneseno (5%) and of Mentha sp. was menthol (92%). Bioassays were carried out by fumigation and topical application. In topical application assays, the essential oil of C. citratus had greater toxicity (LC50 0.027 µL mL-1) and shorter exposure time than the oils of the other two plants. After 24 h and 48 h, 70% and 100% mortality of S. oryzae occurred, respectively. In fumigation assays, essential oil of Z. officinale had a lower LC50 (1.18 µL cm-2) and 70% mortality after 24 h exposure. Therefore, we recommend the use of essential oils of C. citratus and Z. officinale to control the rice weevil S. oryzae.
Resumo:
Interaction betweeen Telenomus remus and Trichogramma pretiosum in the management of Spodoptera spp. The use of egg parasitoids is a promising strategy for Integrated Pest Management (IPM), but different species of parasitoids have greater or lesser control efficiency, depending on the pest species. Recently, not only Anticarsia gemmatalis and Pseudoplusia includens but also Spodoptera cosmioides and S. eridania have been among the key Lepidoptera larvae attacking soybeans. This study evaluated the combination of Telenomus remus and Trichogramma pretiosum for parasitism of eggs of the Spodoptera complex, for better control efficiency and broader spectrum of action among the key pests of soybeans. The experiment was carried out under controlled environmental conditions (25 ± 2ºC; 70 ± 10% RH; and 14 h photophase) in a completely randomized experimental design with seven treatments and 10 replicates with S. frugiperda, S. cosmioides and S. eridania eggs. Each replicate consisted of one egg mass of each Spodoptera species, with approximately 100 eggs offered to the parasitoids. The treatments were: 1) 10 females of T. pretiosum; 2) nine females of T. pretiosum and one female of T. remus; 3) eight females of T. pretiosum and two females of T. remus; 4) seven females of T. pretiosum and three females of T. remus; 5) six females of T. pretiosum and four females of T. remus; 6) five females of T. pretiosum and five females of T. remus, and 7) 10 females of T. remus. The parameter evaluated was the percentage of parasitized eggs. Results showed that treatments combining both parasitoid species with only 1 T. remus for each 9 T. pretiosum (10%) and only 2 T. remus for each 8 T. pretiosum (20%) were enough to significantly increase the parasitism observed on eggs of S. cosmioides and S. frugiperda, respectively. This association of T. pretiosum and T. remus in different proportions is very promising for biological control in IPM programs because it provides wide spectrum of control.
Resumo:
Susceptibility of Alphitobius diaperinus (Panzer) (Coleoptera, Tenebrionidae) to cypermethrin, dichlorvos and triflumuron in southern Brazil. The lesser mealworm, Alphitobius diaperinus (Panzer), is an important insect pest in poultry houses in Brazil. Susceptibility of the lesser mealworm collected from eight poultry houses in Paraná state, southern Brazil, was evaluated for cypermethrin, dichlorvos and triflumuron. Adult A. diaperinus were tested in bioassays with cypermethrin and dichlorvos. Larvae were fed rabbit feed wetted with a triflumuron-water solution. Concentration-mortality regressions were estimated using Probit analysis and resistance ratios were calculated based on the susceptible population. Among the field populations evaluated, cypermethrin LC50 values for adults, ranged from 68.1 to 6,263 ng (AI)/cm². LC50 values for adults challenged with dichlorvos ranged from 10.3 to 1,385 ng (AI)/cm². One population from Pato Branco showed reduced susceptibility to triflumuron (LC50 = 272 µg (AI)/ml of solution) when compared to the most susceptible population (LC50 = 109.8 µg (AI)/ml). Application of cypermethrin and dichlorvos analogues should be managed with caution to minimize insecticide resistance problems.
Resumo:
Host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum in laboratory. This research aimed to evaluate the host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum. Trials were carried out in laboratory, under controlled environmental conditions (25 ± 2ºC temperature; 70 ± 10% RH; and 14 h photophase). The parasitoid searching behavior was evaluated based on the distribution (%) of eggs parasitized by each parasitoid, on egg masses of each host species. Results showed the host preference of T. remus by Spodoptera cosmioides eggs. T. pretiosum, reared in A. gemmatalis eggs, choose to parasitize always eggs of the host where the parasitoid had been reared. The egg preference was not observed when T. pretiosum was reared in S. frugiperda eggs. These results show that, in general, host preference of T. remus is less influenced by the host where it is developed than T. pretiosum. Host preference is an important parameter for biological control programs because more than one pest species may occur in the field, different from those where they were reared in the laboratory.
Resumo:
First record of larvae of Allograpta exotica Wiedemann (Diptera, Syrphidae) preying on Aphis gossypii Glover (Hemiptera, Aphididae) in watermelon in Brazil. Brazil is one of the largest world producers of watermelon (Citrullus lanatus Thumb. Mansf.) and Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) is among the most important pest on this crop. Larvae of Allograpta exotica Wiedemann, 1830 (Diptera, Syrphidae) were found preying on A. gossypii in watermelon crop, in Santa Maria, Rio Grande do Sul State, what represents the first report of this tritrophic association in Brazil.
Resumo:
Effect of silicon and acibenzolar-s-methyl on colored cotton plants infested or not with Aphis gossypii Glover (Hemiptera, Aphididae). The aphid Aphis gossypii is an insect pest that causes damage mainly at the beginning of the cotton plant development. The effect of resistance inductors silicon and acibenzolar-s-methyl (ASM) on the development of colored cotton plants were researched in the presence and absence of A. gossypii. Three colored cotton cultivars were sown in pots and individually infested with 25 apterous aphids, 13 days after the application of the inductors. Fifteen days after plant emergence, the silicon was applied at a dosage equivalent to 3 t/ha and acibenzolar-s-methyl in 0.2% solution of the product BION 500®. After 21 days of infestation the following parameters were evaluated: plant height, stem diameter, dry matter of aerial part and root, and total number of aphids replaced. It was verified that the plant height was reduced in the presence of aphids and all variables were negatively affected by the application of ASM. However, silicon did not affect plant development.
Resumo:
Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera, Tephritidae). Studies on Ceratitis capitata, a world fruit pest, can aid the implementation of control programs by determining the plants with higher vulnerability to attacks and plants able to sustain their population in areas of fly distribution. The objective of the present study was to evaluate the influence of eight tropical fruits on the following biological and behavioral parameters of C. capitata: emergence percentage, life cycle duration, adult size, egg production, longevity, fecundity, egg viability, and oviposition acceptance. The fruits tested were: acerola (Malpighia glabra L.), cashew (Anacardium occidentale L.), star fruit (Averrhoa carambola L.), guava (Psidium guajava L.), soursop (Annona muricata L.), yellow mombin (Spondias mombin L.), Malay apple (Syzygium malaccense L.), and umbu (Spondias tuberosa L.). The biological parameters were obtained by rearing the recently hatched larvae on each of the fruit kinds. Acceptance of fruits for oviposition experiment was assessed using no-choice tests, as couples were exposed to two pieces of the same fruit. The best performances were obtained with guava, soursop, and star fruit. Larvae reared on cashew and acerola fruits had regular performances. No adults emerged from yellow mombin, Malay apple, or umbu. Fruit species did not affect adult longevity, female fecundity, or egg viability. Guava, soursop, and acerola were preferred for oviposition, followed by star fruit, Malay apple, cashew, and yellow mombin. Oviposition did not occur on umbu. In general, fruits with better larval development were also more accepted for oviposition.
Resumo:
This study aimed to evaluate the effects of (g a.i. L-1) abamectin (0.02), carbaryl (1.73), sulphur (4.8), fenitrothion (0.75), methidathion (0.4), and trichlorfon (1.5) on the survival of larvae and pupae, on the oviposition of adults and hatching of eggs from treated Chrysoperla externa third-instar larvae from two different populations (Bento Gonçalves and Vacaria, Rio Grande do Sul State, Brazil). Morphological changes caused by abamectin to eggs laid by C. externa from Vacaria population were evaluated by mean of ultrastructural analysis. The pesticides were applied on glass plates. Distilled water was used as control. For the evaluation of larvae mortality, a fully randomized experimental design in a 2 x 7 (two populations x seven treatments) factorial scheme was used, whereas for the effects of the compounds on oviposition capacity and egg viability, a 2 x 4 factorial scheme was used. Carbaryl, fenitrothion, and methidathion caused 100% mortality of larvae. Abamectin reduced the hatching of eggs from treated third-instar larvae of both populations; however, this pesticide presented highest toxicity on insects from Vacaria. The ultrastructural analysis showed that abamectin caused malformations in micropyle and in chorion external surface of C. externa eggs. Based in the total effect (E), carbaryl, fenitrothion, and methidathion are harmful to C. externa; trichlorfon is harmless to third-instar larvae, while abamectin and sulphur are harmless and slightly harmful to third-instar larvae from Bento Gonçalves and Vacaria, respectively.
Resumo:
Mortality of Plutella xylostella (Lepidoptera, Plutellidae) by parasitoids in the Province of Santa Fe, Argentina. Plutella xylostella (Linnaeus, 1758) (Lepidoptera, Plutellidae) larvae cause severe economic damage on cabbage, Brassica oleracea L. variety capitata (Brassicaceae), in the horticultural fields in the Province of Santa Fe, Argentina. Overuse of broad spectrum insecticides affects the action of natural enemies of this insect on cabbage. The objectives of this work were to identify the parasitoids of P. xylostella and to determine their influence on larva and pupa mortality. Weekly collections of larvae and pupae were randomly conducted in cabbage crops during spring 2006 and 2007. The immature forms collected were classified according to their developmental stage: L1 and L2 (Ls = small larvae), L3 (Lm = medium larvae), L4 (Ll = large larvae), pre-pupae and pupae (P). Each individual was observed daily in the laboratory until the adult pest or parasitoid emergence. We identified parasitoids, the number of instar and the percentage of mortality of P. xylostella for each species of parasitoid. Parasitoids recorded were: Diadegma insulare (Cresson, 1875) (Hymenoptera, Ichneumonidae), Oomyzus sokolowskii (Kurdjumov, 1912) (Hymenoptera, Eulophidae), Cotesia plutellae (Kurdjumov, 1912) (Hymenoptera, Braconidae) and an unidentified species of Chalcididae (Hymenoptera). Besides parasitoids, an unidentified entomopathogenic fungus was also recorded in 2006 and 2007. In 2006, the most successful parasitoids were D. insulare and O. sokolowskii, while in 2007 only D. insulare exerted a satisfactory control and it attacked the early instars of the pest.
Resumo:
Parasitizing behavior of Cervellus piranga Penteado-Dias (Hymenoptera, Braconidae, Braconinae) on papaya borer weevil Pseudopiazurus obesus Marshall (Coleoptera, Curculionidae). The papaya borer weevil Pseudopiazurus obesus is a pest associated with papaya crops in Brazil and Cervellus piranga is a naturally-occurring parasitoid which may contribute to regulate populations of this pest. We aimed at describing the parasitizing behavior of the parasitoid C. piranga on papaya borer weevil P. obesus larvae under field conditions. The sequence of events related to the parasitizing behavior of C. piranga is similar to other braconid species and includes the location and recognition of the attacked host plant followed by walks on the host plant and touching it with the tip of the antennae and the ovipositor. In the following event, the parasitoid assesses the suitability of the host by speeding up antennae and ovipositor movements. After locating and accepting the host, the parasitoid remains inactive on oviposition aperture sites and starts moving the antennae. Afterwards, the parasitoid inserts its ovipositor and starts cleaning it repeatedly. The female of C. piranga inserts the ovipositor through the hole and lay one egg into the papaya weevil borer. After oviposition, the female cleans continuously both ovipositor and antennae before leaving to forage for a new host.
Resumo:
An experimental test of rainfall as a control agent of Glycaspis brimblecombei Moore (Hemiptera, Psyllidae) on seedlings of Eucalyptus camaldulensis Dehn (Myrtaceae). Glycaspis brimblecombei is one the greatest threats to eucalyptus plantations in Brazil. The effects of rainfall to reduce the abundance of lerp of Glycaspis brimblecombei on experimentally infested seedlings of Eucalyptus camaldulensis were assessed. The number of lerps on the adaxial and abaxial surfaces of every leaf of 60 seedlings was recorded, before and after submission to the following treatments: "artificial rain", "leaf wetting" and control. A drastic reduction in lerp abundance per plant was observed after the treatments "leaf wetting" and artificial rain (F = 53.630; p < 0.001), whereas lerp abundance remained roughly constant in the control treatment along the experiment (F = 1.450; p = 0.232). At the end of the experiment, lerp abundance was significantly lower in both the "artificial rain" and "leaf wetting" than in the control treatment. Two days of rainfall simulation were sufficient to decrease more than 50% of the lerp population, with almost 100% of effectiveness after 5 days of experiment. Our results indicate that lerp solubilization and mechanical removal by water are potential tools to the population regulation of G. brimblecombei on E. camaldulensis seedlings.
Resumo:
First report and morphological redescription of Teleonemia morio (Stål) (Hemiptera, Tingidae) in Annona squamosa L. (Annonaceae) in Brazil. This is the first report of a severe attack of Teleonemia morio (Stål, 1855) (Hemiptera, Heteroptera, Tingidae) on Annona squamosa L. (custard apple), causing up to 80% of losses of infested trees. In order to facilitate the identification of this insect pest, the adult female of T. morio is redescribed based on specimens collected in Palmeira dos Índios, Alagoas, Brazil.
Resumo:
Occurrence of adults and biological aspects of Geniates borelli Camerano (Coleoptera, Scarabaeidae, Rutelinae) in Aquidauana, Mato Grosso do Sul, Brazil. Due to the importance of Geniates borelli Camerano as a pest in many crops, studies were developed at Universidade Estadual de Mato Grosso do Sul, Aquidauana campus, MS, Brazil. Adults were collected with a light trap from January 2006 to December 2007. 3,320 adults were collected, and the highest quantities were obtained in October 2006 and November 2007, with 1,548 and 802 adults recorded, respectively. Collected adults were kept in plastic containers with soil and Brachiaria decumbens seedlings for oviposition. 535 eggs measuring 2.30 × 1.60 mm were obtained. As the embryonic development progressed, eggs increased in size to 3.00 × 2.70 mm, and this change occurred between 6 and 10 days after oviposition. The embryonic period lasted 17.9 days. The first, second, and third instars lasted 37.6, 49.7, and 74 days, respectively. The prepupal stage lasted 65.9 days and the pupal stage lasted an average of 18.5 days. The biological cycle is completed in 315.8 days, which characterizes the species as univoltine. The average longevity of females was 35.4 days and 28.5 days for males.