We studied Spodoptera frugiperda development using different food sources in the laboratory and field. Newly hatched larvae were fed soybean, cotton, maize, wheat, and oat leaves. An artificial diet was used as the control. Duration of pre-pupal, pupal, and larva-adult period, pupal weight, sex ratio, survival, larva feeding preferences, oviposition preferences, and nutritional quality of different hosts were evaluated. Insects fed on wheat showed the shortest larva-adult period. The insects fed on cotton and soybean had longer larval development cycles and pupae of lower weight. Feeding preference was evident for third instar larvae and did not differ between wheat, oat, maize, and soybean, which were the preferred hosts. Moths oviposited to a greater extent on the upper canopy of wheat than that of other plants in both the no-choice and free-choice tests. Treatments influenced insect growth, food consumption, and digestion when nutritional variables were analyzed. Thus, grasses were better hosts for S. frugiperda development. Cotton was the least preferred food, followed by soybean. The present study can improve our understanding of S. frugiperda in these different crops and help in developing management strategies. Even though S. frugiperda is considered to be polyphagous, this pest is closely associated with grasses (maize, wheat, oat) and has lower potential as a soybean or cotton feeder. Howerver, S. frugiperda food intake regulation appears to be triggered by a complex of different mechanisms. Thus, S. frugiperda can also damage soybean and cotton and adapt to them in the absence of preferred hosts.
Pesticides are considered the first line of defense for the control of pests and diseases. At least in the short and medium term, the use of pesticides will remain an important strategy for pest management, allowing growers to produce crops of sufficient quality at low costs. A broad approach known as Integrated Pest Management (IPM) combines several different pest-control strategies, among which the combination of chemical and biological control stands out. It requires pesticides that achieve optimal control of target pests with minimal impact on the activity of biological control agents. Because of the dynamics of pest infestations, IPM routines are continuously adjusted by growers, requiring comprehensive information about pesticide effects on natural enemies. However, this information is not always available and often contradictory, which constrains the design of field recommendations. In this review, we focused on the importance of selective pesticides in IPM programs, and the effects of chemical pesticides on parasitoids, predators, and entomopathogenic fungi. We provided a detailed discussion of the challenges and constraints for research on pesticide effects on natural enemies, as well as for the resulting field recommendations.
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Chrysodeixis includens (Walker 1858), also known as soybean looper, is a polyphagous pest with increasing economic significance in various crops. The rate of infestation and its distribution can be influenced by feeding through direct and indirect effects on their life cycles. Thus, this study aimed to examine the biological characteristics, food preference and leaf consumption of C. includens on soybean (BRS 284), cotton (FMT 701), sunflower (BRS 323) and common morning glory leaves (Ipomoea sp.) as possible host plants. The experiments were conducted with specimens obtained from mass rearing in the laboratory. C. includens larval and larval-adult stages were shorter in sunflower and longer in cotton. Also, larval preference was greater for sunflower and lower for cotton leaves. Soybean leaves were consumed the least in contrast to sunflower and common morning glory leaves, which were consumed the most. These results suggest that soybean, sunflower or common morning glory leaves were favourable hosts for C. includens development, whereas cotton leaves are less nutritionally adequate for insect development. In addition, sunflower leaves reduce C. includens development time and promotes a survival rate greater than 95%, and the leaves are more attractive to larvae when compared with the other tested hosts. This indicates sunflower is the most favourable host among the tested plants for C. includens.
RESUMO -Este trabalho avaliou a seletividade de inseticidas a adultos de Doru lineare. Os testes foram conduzidos em condições controladas. Os inseticidas testados (g i.a. ha -1 ) foram: flubendiamida (72); clorantraniliprole (30); clorantraniliprole (15) + lambda-cialotrina (7,5); lambda-cialotrina (7,5); clorpirifós (480); e controle (água destilada).Os tratamentos foram aplicados em arenas compostas de placas de vidro (área 169 cm 2 ), aprisionando o inseto com anéis de PVC. A extremidade superior do anel foi protegida com tecido fino (tule), onde os adultos receberam aplicação tópica dos inseticidas através de Torre de Potter. A sobrevivência dos insetos foi avaliada 24, 48, 72, 96 e 120 horas após a exposição dos adultos aos tratamentos. Flubendiamida e clorantraniliprole foram classificados como inócuo (classe 1) a D. lineare e, portanto, são apropriados para uso em programas de Manejo Integrado de Pragas (MIP) porque podem ser aplicados preservando o controle biológico natural. Clorpirifós, lambda-cialotrina e clorantraniprole + lambdacialotrina foram nocivo (classe 4), moderadamente nocivo (classe 3) e levemente nociva (classe 2), respectivamente.Produtos não seletivos precisam ser também testados em semi-campo e campo para avaliar a persistência. Inseticidas nocivos e persistentes devem, sempre que possível, ser substituídos por outros mais seletivos.ABSTRACT -This study aimed at assessing selectivity of insecticides to adults of Doru lineare. The tests were performed under controlled environmental conditions. Insecticides tested (g a.i. ha -1 ) were: flubendiamide (72); chlorantraniliprole (30); chlorantraniliprole (15) + lambda-cyhalothrin (7.5); lambda-cyhalothrin (7.5); chlorpyriphos (480); and control (distilled water). Treatments were sprayed over arenas made up with glass plates (area 169 cm 2 ), imprisoning the insect with PVC rings. The top of the rings was protected with a fine fabric (tulle) where adult insects were sprayed with insecticides using a Potter Tower. Insect survival was assessed at 24, 48, 72, 96, and 120 h after exposing adults to the treatments. Flubendiamide and chlorantraniliprole were classified as harmless (class 1) to D.lineare and therefore apropriated to be used in Integrated Pest Management (IPM) programs since they can be sprayed preserving natural biological control. Chlorpyriphos, lambda-cyhalothrin and the mixture of chlorantraniliprole + lambda-cyhalothrin were harmful (class 4), moderately harmful (class 3), and slightly harmful (class 2), respectively.Non-selective products should also be tested in semi-field and field conditions to evaluate its persistence. Whenever possible, noxious and persistent insecticides should be replaced for more selective ones.
The present study evaluated the effect of different rates of chlorantraniliprole, chlorantraniliprole + lambda-cyhalothrin, spinosad, and chlorfenapyr on their selectivity for the pupae and adults of Trichogramma pretiosum. The negative effect of majority of the insecticides tested on most of the parasitoids was directly proportional to the rate of the insecticide applied. Chlorantraniliprole at a rate of 10 g a.i. ha -1 was classified as harmless (class 1) to both pupae and adults of the parasitoid. The effect of chlorantraniliprole at a rate of 20 to 50 g a.i. ha -1 varied from harmless (class 1) to slightly harmful (class 2) to the adults of T. pretiosum. Chlorantraniliprole 10 + lambda-cyhalothrin at 5 g a.i. ha -1 was classified as harmless (class 1) to the pupae and moderately harmful (class 3) to the adults of T. pretiosum. On the contrary, the highest rate of chlorantraniliprole 50 + lambda-cyhalothrin tested (i.e., 25 g a.i. ha -1 ) was classified as slightly harmful (class 2) to the pupae and harmful (class 4) to the adults of the parasitoid. Similarly, increasing the application rate of spinosad and chlorfenapyr also exhibited an increase in toxicity. Spinosad at a rate of 24 g a.i. ha -1 was classified as slightly harmful (class 2) and harmless (class 1) to the pupae and adults of T. pretiosum, respectively. Spinosad at 96 g a.i. ha -1 was classified as both moderately harmful (class 3) and harmful (class 4) to the pupae of the parasitoid. Chlorfenapyr at a rate of 192 g a.i. ha -1 was classified as both slightly harmful (class 2) and moderately harmful (class 3) to the pupae of T. pretiosum, whereas chlorfenapyr at 336 g a.i. ha -1 was categorized as slightly harmful (class 3) and harmful (class 4) to the pupae. These results indicate that an increase in the rate of insecticide affected T. pretiosum negatively. Therefore, higher insecticide rates should only be adopted when strictly necessary to control the target pest, because they might compromise the biological pest control process in the field. ResumoO presente estudo avaliou o efeito de diferentes taxas de clorantraniliprole, clorantraniliprole + lambdacialotrina, espinosade, e clorfenapir na seletividade para as pupas e adultos de Trichogramma pretiosum. O efeito negativo da maioria dos inseticidas testados nos parasitoides foi diretamente proporcional à dose do inseticida aplicado. O clorantraniliprole na dose de 10 g a.i. ha -1 foi classificado como seletivo (classe 1) para pupas e adultos do parasitoide. O efeito do clorantraniliprole na dose de 20 a 50 g a.i. ha -1 variou de seletivo (classe 1) a levemente prejudicial (classe 2) aos adultos de T. pretiosum. Clorantraniliprole 10 + lambda-cialotrina a 5 g a.i. ha -1 foi classificado como seletivo (classe 1) para as pupas e moderadamente prejudicial (classe 3) aos adultos de T. pretiosum. Ao contrário, a dose mais alta de clorantraniliprole 50 + lambda-cialotrina testada (isto é, 25 g a.i. ha -1 ) foi classificada como moderadamente prejudicial (classe 3) para as pupas e nociva (cla...
The selectivity of different insecticides to nymphs and adults of Podisus nigrispinus was evaluated in this study. Tests were carried out in the laboratory according to IOBC standard protocol. We evaluated different active ingredients that were applied using a Potter tower. Insect survival was assessed at 24-hour intervals for up to five days after exposure to treatments. Adult survivors of each treatment were assigned to breeding-pairs to evaluate possible effects on fertility. The pyrethroids bifenthrin, zeta-cypermethrin, beta-cyfluthrin, lambda-cyhalothrin and deltamethrin alone or in mixtures with neonicotinoids and diamides, such as beta-cyfluthrin + imidacloprid, lambda-cyhalothrin + thiamethoxan and chlorantraniliprole + lambda-cyhalothrin, as well as the organophosphate, chlorpyrifos, were the most harmful (class 4 classification) insecticides for the preservation of P. nigrispinus for both nymph and adult predators. Conversely, the insecticide growth regulators (IGRs) lufenuron, teflubenzuron, triflumuron, tebufenozide and novaluron were classified as harmful (class 4) only for P. nigrispinus nymphs. These products were classified as harmless (class 1) and slightly harmful (class 2) for adult predators. Among the evaluated products, the most selective for P. nigrispinus were those belonging to the spinosyns (spinosad and spinetoram) and the diamides group (flubendiamide and chlorantraniliprole), which were classified as harmless (class 1) and slightly harmful (class 2) for both P. nigrispinus nymphs and adults. Next, the most selective product was methoxyfenozide, which ranged between slightly harmful (class 2) and moderately harmful (class 3) to nymphs and harmless (class 1) to adults of the natural enemy. Key words: Biological control. Chemical control. Natural enemy. IOBC. sobre a fertilidade. Os piretróides bifentrina, zeta-cipermetrina, beta-citflutrina, lambda-cialotrina e deltametrina isolados ou em misturas com neonicotinóides e diamidas, tais como beta-citflutrina + imidacloprid, lambda-cialotrina + tiametoxano e clorantraniliprole + lambda-cialotrina, bem como o organofosforado, clorpirifós, foram os inseticidas mais nocivos (classe 4) para a preservação de ninfas e adultos do predador P. nigrispinus. Por outro lado, os reguladores de crescimento de inseticidas (IGRs) lufenuron, teflubenzuron, triflumuron, tebufenozide e novaluron foram classificados como nocivos (classe 4) apenas para ninfas de P. nigrispinus. Estes produtos foram classificados como inofensivos (classe 1) e levemente nocivo (classe 2) para os predadores adultos. Entre os produtos avaliados, os mais seletivos para P. nigrispinus foram aqueles pertencentes às espinosinas (spinosad e spinetoram) e ao grupo das diamidas (flubendiamida e clorantraniliprole) classificados como inofensivos (classe 1) e levemente nocivos (classe 2) para ninfas e adultos de P. nigrispinus. Em seguida, o produto mais seletivo foi methoxyfenozide, que variou entre ligeiramente prejudicial (classe 2) e moderadamente prejudicial (classe 3) para n...
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