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| Author(s): |
Gabriel Gonçalves Monteiro
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Jaboticabal. 2022-10-18. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal |
| Defense date: | 2022-09-15 |
| Advisor: | Nilza Maria Martinelli; Ana Lúcia Benfatti Gonzalez Peronti |
| Abstract | |
The sugarcane crop Saccharum spp. (Poales: Poaceae) makes Brazil the world's largest producer. Despite of agronomic strategies used, phytosanitary issues such as insect pests and phytopathogenic diseases stand out. The pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) and the red rot fungus Colletotrichum falcatum Went are commonly found in sugarcane crops. In order to understand the performance of the insect pest, related or not to a phytopathogenic agent, it is necessary to study its biological development and the direct and indirect damages that it can cause. This study aimed to evaluate the biological development of S. sacchari under different temperatures, to analyze the biometric and technological characteristics in different phenological stages of sugarcane plants, infested by the mealybug, and to estimate the perforations caused by the pseudococcid through different numbers of the insect and to confirm by Scanning Electron Microscopy (SEM) the mealybug-rot complex. For the analysis of the biological development, gravid females and sugarcane stalks were collected. The stalks were infested with mealybugs, individualized in Petri dishes and kept in two BODs (23 °C ± 2 °C and 28 °C ± 2 °C). The number of eggs, viable and nonviable eggs, incubation time, timing of the last oviposition, nymph hatching, timing of each instar, mortality of nymphs, emergence time and adult longevity were recorded daily. Pseudococcids reproduce by thelytocal parthenogenesis. Under laboratory conditions, the increase in temperature favors the longevity of the insect with three phases of growth. In the study of direct damage, sugarcane plants were infested, at each phenological stage, by gravid mealybugs. The plants were submitted to external biometrics, and in the ripening stage, the technological data were obtained. It was found that the insect infestations at all phenological stages reduce the physical characteristics of the plants, but not the qualitative technological chemistry. To accomplish the last objective, fragmented stems were infested with different numbers of the pseudococcid by geometric progression, and stems infested by the pseudococcid and infected by C. falcatum were collected. The stalks from each treatment were immersed in 1% acid fuchsin solution and the holes were counted. Isolated samples of the pink sugarcane mealybug, the pseudococcid with the mouthparts in plants, the red rot fungus and the mealybug-rot complex were observed under Scanning Electron Microscopy (SEM). It was obtained that the number of holes caused by S. sacchari ranged between 5.3 and 30.3, being dependent on the proof perforations, number of individuals, the area available for feeding and on the survival of the first, second and third instar nymphs that reached the adult stage. The veracity of the hypothesis of the mealybug-rot complex in sugarcane plants is confirmed. (AU) | |
| FAPESP's process: | 19/24149-0 - Biological aspects and damages of Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) in sugar cane |
| Grantee: | Gabriel Gonçalves Monteiro |
| Support Opportunities: | Scholarships in Brazil - Doctorate |