According to the analysis of the occurrence trend of the main citrus diseases and insect pests in the first half of this year by the experts of the whole city and the surrounding counties and cities, combined with the investigation of the base number of Citrus Diseases and insect pests in our county, the occurrence of Citrus Diseases and insect pests over the years, the comprehensive analysis of cultivation management and meteorological conditions, etc., it is estimated that the main citrus diseases and insect pests in the first half of this year in the whole county will occur in a medium degree, and the occurrence trend will be partial. Among them, the occurrence of citrus red spider is more serious, the occurrence of leafminer moth, citrus whitefly, aphid, scab, anthrax and resinous disease are moderate, and the occurrence of other diseases and insect pests is light to light.
1、 Occurrence trend forecast
1. Starscream: it is prone to occurrence, similar to last year, with an estimated area of about 55%.
2. Leafminer: moderate occurrence, similar to last year, estimated occurrence area is about 30%.
3. Aphid: moderate occurrence, heavier than last year, estimated occurrence area is 30-40%.
4. Citrus whitefly: moderate occurrence, partial preference, similar to last year, with an estimated area of about 35%.
5. Citrus Psylla: light occurrence, moderate in some parts, heavier than last year, estimated occurrence area is about 20%.
6. Scale: light occurrence, similar to last year, estimated occurrence area is about 10%.
7. Rust ticks: light occurrence, partial partial occurrence, slightly heavier than last year, with an estimated area of about 15%.
8. Anthrax: moderate occurrence, heavier than last year, with an estimated area of about 35%.
9. Scab: moderate occurrence, heavier than last year, with an estimated area of about 40%.
10. Resin disease (blackspot): moderate, similar to last year, with an estimated area of 30%.
11. Yellow Dragon disease and longicorn were moderate to severe in some orchards.
2、 Forecast basis
1. Base number of diseases and insect pests: according to the investigation of base number after winter, there are more than 500 red spider shutters, more than 20 citrus whitefly shutters, 0-3 citrus planthopper treetops, more than 10% of scab disease leaf rate, 12% of resin disease leaf rate, and 0-62 scale insect shutters.
2、 Cultivation and management: the temperature in the last winter was high, the orchard was not cleaned thoroughly, the management was extensive, the tree vigor was weak, and the resistance was decreased; the area of high grafting orchard was increased, the shoot growth period was different, and the number of shoots was more, which was conducive to the occurrence of diseases and pests.
3. Climate factors: the meteorological department estimates that the average rainfall in 2020 flood season (April to June) is slightly more, and some areas may be flooded or waterlogged, which is conducive to the occurrence of diseases and insect pests.