The drop rate of 21,60% recorded in the 2020/21 harvest is the highest ever measured by Fundecitrus since the beginning of the Harvest Estimation Survey (PES) in 2015. If the fruits that fell had reached harvest, they would represent the equivalent of approximately 74 million boxes.
Until now, the rate of 17,63% measured in the 2019/20 harvest was the highest measured by Fundecitrus. In previous years, the numbers were 16,70% (2018/19), 17,30% (2017/18) and 13,73% (2016/17).
Severe drought and the high incidence of greening, ferret bugs and fruit flies are the main causes of the record number of fallen fruits this harvest. See complete list and number of lost boxes:
1st Natural or mechanical: 6,63% (22,72 million boxes)
2nd Ferret and fruit fly: 4,76% (16,31 million boxes)
3rd Greening: 3,71% (12,71 million boxes)
4th Black spot: 2,98% (10,21 million boxes)
5th Leprosy: 1,70% (5,82 million boxes)
6th Crack: 1,45% (4,97 million boxes)
7th Citrus canker: 0,37% (1,27 million boxes)
The unfavorable weather began in September and October 2019, with dry weather and high temperatures that hampered the setting of newly formed fruits, resulting in a lower concentration of oranges in the main bloom. During the fruit development phase, drought and heat intensified with the arrival of climate phenomena such as La Niña.
According to the coordinator of the Harvest Estimation Research (PES) at Fundecitrus Vinícius Trombin, the strong influence of weather conditions was decisive in most of the citrus park in 2020 – some regions spent up to 145 days in a row without significant rain and a heat wave extreme made September and October the hottest months, with temperatures, respectively, 4,4 oC and 3,1 oC above the historical maximum averages. “This combination caused the highest rate of decline ever measured,” he comments.
This year, the crack gained prominence on the list due to its significant rates. Previously, it was included in “natural or mechanical”. The extremely severe drought caused the bark to lose its plasticity.
In addition to the strong impact of adverse weather, the restrictions imposed by the pandemic may also have affected the adequate management of orchards.
Citrus diseases and pests caused the loss of 46,32 million boxes, which corresponds to 13,5% of the drop rate. In this group, fruit flies and ferrets were the main reason for the population increase of these insects, observed since the 2018/19 harvest. To alleviate the problem, it is essential to carry out correct control.
“Monitoring must be carried out before the fruits mature, and, if an increase in population levels is detected, control must be carried out. To do this, it is necessary to use traps with pheromones for ferrets and food attractants for fruit flies”, recommends Fundecitrus researcher Marcelo Miranda.
Greening appears second on the list due to the continuous growth in the incidence and severity of the disease, coupled with the failure to eliminate diseased trees in some orchards. “The maintenance of plants with greening without frequent control of the psyllid, in addition to intensifying the severity of the disease, also favors the appearance of new plants with symptoms. Greater incidence and severity of HLB lead to a higher rate of falls and losses”, highlights Fundecitrus researcher Renato Bassanezi.
The multiple blooms of this harvest made control of early blight more difficult, causing an increase in the disease's share of the decline rate, after three years of stability. To avoid fruit falling, it is necessary to invest in appropriate management. “Fungicides should be used during the period of more frequent and intense rain. Copper, in less favorable times for the disease, and strobilurins in more favorable times. In more critical orchards, management should not be terminated before the rains. The sprayers need to be regulated and calibrated with the appropriate volume and doses and the orchards must be pruned so that the plant branches do not touch the nozzles, which would affect the application”, explains Fundecitrus researcher Geraldo Silva.
The leprosy rate, although low, has continued to increase in the last five years. The extremely adverse climate in this harvest was also favorable to the mite that transmits the virus, in addition to negatively influencing acaricide applications, with greater loss of sprayed drops due to evaporation.
However, Bassanezi highlights that growth is associated with difficulties in controlling the vector. “Some measures, such as frequent and rigorous monitoring of the mite, immediate application of acaricides after detecting their level of action, use of the correct volume of spray solution and alternation of products are important for efficient management”, he mentions.
To avoid errors in managing leprosis, check out the article “Difficulties in control” in issue No. 44 of Citricultor magazine, in https://www.fundecitrus.com.br/comunicacao/revistas.
The Centro sector presented a drop rate above the average for the citrus belt due to the high incidence of orange trees with greening and the large number of trees with high severity of the disease. This sector is among those with the highest incidences of HLB: 29,76%, according to the latest Fundecitrus greening survey, in 2020.
In the Northwest, the higher rate was due to the greater water deficit.
Decline rate by sector:
North: 17,96%
Northwest: 23,74%
Center: 27,03%
South: 20,34%
South-west: 19,60%
The rate of decline in Florida (USA) is almost double compared to the citrus belt: 41,92%, according to a calculation by Fundecitrus based on average rates for early, mid-season and late, released by the State Department of Agriculture United States (USDA).
The highest rate measured so far was 56,53%, in the 2017/18 harvest. In the two subsequent harvests, the rates were 25,47% and 29,03%, respectively. The main factors for the greater fruit drop this year were adverse weather and greening, which affects approximately 90% of plants in the state.
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