This article has been cited by other articles in PMC. Abstract This research aimed to assess the toxicity of the pesticides abamectin 18 CE 0. L-1 , carbaryl SC 1. L-1 , sulfur GrDA 4. L-1 , fenitrothion CE 0.
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This article has been cited by other articles in PMC. Abstract This research aimed to assess the toxicity of the pesticides abamectin 18 CE 0. L-1 , carbaryl SC 1. L-1 , sulfur GrDA 4. L-1 , fenitrothion CE 0. L-1 , methidathion CE 0. L-1 , and trichlorfon SC 1. An attempt was made to study morphological changes caused by some of these chemicals, by means of ultrastructural analysis, using a scanning electronic microscope.
Trichlorfon was also harmless to adults from both populations. No compound reduced oviposition capacity. In relation to egg viability, sulfur was the most damaging compound to both populations of C. Ultrastructural analyses showed morphological changes in the micropyle and the chorion of eggs laid by C. The treatment may have influenced the fertilization of C. Sulfur was responsible for malformations in the end region of the abdomen and genitals of treated females.
When applied to adults, abamectin, sulfur, and trichlorfon were harmless, while carbaryl, fenitrothion, and methidathion were harmful, according to the IOBC classification. Keywords: biological control agents, green lacewings, natural enemies, scanning electronic microscopy Introduction The apple tree was introduced to Brazil in the s in Fraiburgo, Santa Catarina.
Currently the apple tree is considered the most important fructiferous tree of temperate climate cultivated in the country; it has great significance in the domestic market and for exports as well Silva et al.
Despite its recent cultivation in Brazilian lands, the national pomiculture is not only supplying the domestic market, but is also establishing itself gradually in international trade and European markets. However, the imposed exigencies by this and other consuming markets have forced Brazilian producers to adapt to new methods of fruit production, in other words, integrated production. This system permits the production of better-quality fruits, the reduction in pesticide-use, and the possibility of tracking the final product.
In integrated production, there are great efforts to control pests by increasing natural factors of mortality using biological agents such as parasitoids, predators, and entomopathogens, with the focus on predators that are able to consume great quantities of prey.
Among the predators, insects belonging to the family Chrysopidae have been considered voracious organisms with strong adaptability to different agroecosystems Senior and McEwen ; Medina et al. Past research has demonstrated that Chrysoperla externa Hagen Neuroptera: Chrysopidae are effective predators of mites on apples Miszczak and Niemczyk In Brazil, C. In this context, the use of selective pesticides, which control pests without affecting the populations of natural enemies in a negative way, constitute an important strategy in the integrated management of pests Moura and Rocha It is important to identify and develop selective products and to determine the factors that affect behavior, development, and reproduction of beneficial organisms in a way that can be used in conjunction with biological methods of pest control in the apple tree crop.
The objective of this work was to assess the effects of certain pesticides used in integrated apple production in Brazil on the survival and reproduction of adults of C. Materials and Methods The rearing and maintenance of both populations of C. Following the techniques described by Auad et al. Pesticides Commercial formulations of abamectin 18 CE 0. L-1 , recommended for use in integrated apple production in Brazil, were used in the bioassays with adults of C. Distilled water was used as the control.
Bioassays Fifteen pairs each pair constituted by one male and one female of C. Although adult male and female C. Males have a small rounded capsule flanked by two small projections, while females have an oval area bounding a longitudinal slit. After application of pesticides and distilled water, each pair was transferred to a PVC cage 7. The evaluations took place at 3, 6, 12, 24, 48, 72, 96, and h after application with the goal of determining the mortality rate of the treated C.
Six pairs of C. The evaluations began three days after the applications and continued twice a day with 12 hour intervals until the start of oviposition. Four consecutive weeks after the start of the oviposition, the number of eggs deposited was counted at three-day intervals.
Ninety-six eggs by treatment were separated into microtitration plate compartments using a camel hair brush. The plates were closed with a PVC film and kept under controlled conditions until the eggs hatched, when egg viability was evaluated.
The oviposition capacity and egg viability of treated C. Five replicates were used, with the experimental plot constituted by three pairs of C. For the oviposition evaluation, six replicates were used, and each plot was constituted by a C.
The pesticides were then classified based on the reduction of beneficial capacity and mortality caused to the predator using Equation 1, proposed by Vogt Statistical analysis The obtained data in the bioassays with C. The mortality data obtained from the bioassays with C. Data referring to the oviposition from females treated with pesticides as well as distilled water control were subjected to a model analysis using the software R R Development Core Team GLM mode Generalized Linear Models with negative binomial distribution of error logarithmic linkage function for the over dispersion correction was applied for the output variable of oviposition Crawley The following input variables were used to fit the model: C.
Residual analyses with envelope approach generating probability distribution graphs of Normal Gauss , Poisson, Binomial, and Negative Binomial Pascal were performed to verify how the data fit the models Paula The best fitting model choice to oviposition data collected were the graphs plotted by the envelope approach and the AIC index Akaike Information Criteria Akaike ; apud Paula , as well as in the relationship between the deviance and degrees of freedom of the residue.
After the choice of the model, the necessary parameters estimates were calculated Table 1 allowing the oviposition equations to be constructed for both C. Then, a program was developed to adjust several possibilities of the oviposition predator with all the equations being based on the general one Equation 2 that follows. Table 1. Open in a separate window Ultrastructural analysis of C. Twenty newly laid eggs were used per treatment; they were transferred to plastic containers Eppendorf, www.
Results Six hours after the application of the pesticides, no compound had caused the death of any C. Sulfur and abamectin also caused mortality of 6. Trichlorfon was harmless to adults of both populations, and trichlorfon and sulfur did not change the mortality pattern of any population throughout evaluation process Table 2.
Table 2. Open in a separate window Oviposition capacity of surviving C. Females from Vacaria had similar variations when treated with trichlorfon or sulfur Table 3. Table 3. Open in a separate window It was also verified that the peak of oviposition for all treatments happened near the 15th day after the beginning of oviposition, regardless of the population.
The mean amount of eggs varied from Oviposition capacity of C. In all evaluated treatments from the 27th day of oviposition, oviposition capacity varied from Analysis of the data to develop a model that fit the obtained data and generation of equations that aim to predict C.
Oviposition modeling Figure 1 showed that trichlorfon, followed by abamectin, were the most harmful compounds. These compounds affected oviposition of C. Oviposition behavior for females treated with the different pesticides was similar for both populations.
Chrysoperla externa una alternativa en el control biológico de plagas