Uso de extratos de plantas da caatinga no controle da cochonilha-do-carmim (Dactylopius opuntiae) em palma forrageira (Opuntia ficus-indica)

Abstract

The Brazilian semiarid region is a region with poorly defined seasons and vegetation with different vegetation types, known as Caatinga vegetation, being one of the only exclusively Brazilian ecoregions. Fodder crops are adopted by farmers as an alternative strategic supplementation of animals, appropriate to the season. Opuntia ficus-indica, known as cactus pear, is a crop well adapted to semi-arid conditions and their species possess physiological properties related to absorption, utilization and water loss, is an important forage for food subsidy herds during periods of prolonged drought. Dactylopius opuntiae, popularly known as the cochineal carmine, is a major pest of cactus pear, whose continuous feeding process and increased infestation weakens the plant, causing irreversible damage and causing the death of rackets in short time. Chemicals are often used as a control measure for this pest, but overuse of these products and disoriented harms agroecosystems affects living organisms and cause contamination by toxic waste. Chemicals obtained from plant species are one of the alternatives for pest control in order to reduce damage to the environment. Because of such problems, this study aimed to aqueous extracts of botanical species in the Caatinga, for the control of cochineal carmine in the cactus pear, being divided into three chapters. For this, we used aqueous extracts of bean-bravo (Cynaphalla flexuosa), Quince (Croton blanchetianus) and Juazeiro (Ziziphus joazeiro) and distilled water as a control. In Chapter I, the extracts were applied in rackets likely in laboratory conditions, and infested by nymphs migrants from the cochineal carmine, in order to analyze mortality. 4 measurements were used to obtain the aqueous extract (1, 5, 10 and 15g/100 ml) of plant species. In the laboratory were tested doses 0, 1, 5, 10 and 15% of treatments discs capable of forage, and then dipped colonized by migrant nymphs, which were analyzed every 6 hours for a period of 48 hours for analysis of mortality of nymphs. With the results obtained in laboratory, a dose was chosen for use in other experiments. In Chapter II, 100mL treatments were applied on palms forage likely cleaned, placed in wooden cages, to analyze the speed of mealybug infestation of colonies after obtaining statements from 5g of plants.The experiment was analyzed daily for a period of 30 days, counting the number of nymphs and migrant colony of cochineal carmine present in the treated rackets. In Chapter III, extracts and insecticide (lambda + Thiamethoxam) were applied to populations dae cochineal carmine in the planting of forage in two experimental areas, being used 3L of aqueous extracts and spray the insecticide, obtained from 150g and 1.51 mL of the insecticide, which were evaluated at 8 and 15 days after installation of the experiment to area in Sierra Hewn, and 10 and 15 days for the area of São José do Belmonte, with reapplication of treatments in the first evaluation. The data obtained in the experiments were tabulated and submitted to analysis of variance and the means were compared by Tukey test at 5% probability, and for field experiments was estimated instantaneous rate of increase (ri) of the plague. In the laboratory all extracts caused mortality of nymphs of D. migrants opuntiae been observed that mortality increases with dose and exposure period. In the experiment of infestation, it was realized that the beginning of colonization by nymphs migrants and colonies of cochineal carmine occurred in the first 10 days of evaluation, presenting a significant interaction extracts and extracts * dose * time of evaluation. In the field, the two experimental mortality was more than 50% of the colonies of the cochineal carmine when treated by the extracts, which resulted in an instantaneous rate of increase (ri) negative population of mealybugs. The results of this study demonstrated the feasibility of using plants of Caatinga in the management of cochineal carmine in the cactus pear, since the use of plant species becomes a practice of easy access and low-cost production.