LIBRO-CONGRESO-CITRUS

Health. We have to guarantee our consumers that what they buy in our shops is healthy. And furthermore,
that those citrus have been grown packed and transported in legal and safe conditions.
Spain is a privileged area. Since centuries, weather and soil have provided the optimal environment for
growing citrus. But the global context also counts. Therefore, we all are obliged to keep on working on the
same axes: quality and efficiency. As grower, sometimes size can be a difficulty. There are several production
areas, like in the Valencia Region, where orchards average surface is quite small. Maybe getting closer to a
professional good organization with good positioning in the market, good knowledge of varieties and trends
could help. On efficiency, maybe working together and sharing cultural practices costs could help small
growers. I understand it is always better to do everything by yourself, not depending on anyone. But, unless
you are big enough and efficient enough, world is pushing in the other direction: teamwork.
To keep a place in the market is always a challenge. And we all have to work hard to achieve it. But I invite you
all to take profit of your unique conditions and keep on making consumers from all over the world, enjoying
these magnificent fruits you are able to produce.
PC05
The experience of Huanglongbing control in Brazil
Antonio Juliano Ayres
Fundo de defesa da citricultura (FUNDECITRUS). Brazil
Symptoms of Huanglongbing (HLB) were first reported in São Paulo State (SPS) near Araraquara in 2004.
However, the insect vector, the Asian citrus psyllid, Diaphorina citri, has been present in SPS since 1940 and
is responsible for the spread of HLB to most regions of SPS.
Immediately after HLB was identified in March 2004, Fundecitrus recommended HLB-management in all
the citrus farms of SPS as an attempt to control the disease and save the industry from destruction. The
management involved three classic measures: (i) insecticide sprays of all trees, several times a year, to decrease
the insect-vector population, (ii) identification and immediate removal of symptomatic trees, several times a
year, to rid orchards of sources of inoculum, and (iii) replacement of removed trees by young, HLB-free trees
from covered, insect-proof nurseries. HLB-management by this “three-pronged system” (TPS) was evaluated
by determining the total number of symptomatic trees removed each year in the various blocks. Indeed,
successful management would result in decrease of the total number of symptomatic trees removed per year,
while unsuccessful management would lead to an increase of such trees.
Since 2004, crucial factors having a strong influence on HLB-management by the TPS have been identified.
1) HLB incidence in the region where the farm is located and 2) HLB incidence in the farm. For instance,
when HLB is first detected in a region or country where the psyllid vector has been present for some time
(Brazil in 2004, Florida in 2005, Texas and California in 2012) the incidence of the disease is generally low.
HLB management by the TPS is easier when the HLB incidence at onset of the management is low (≤ 7%).
3) When a farm with good HLB management is close to a farm with no or poor management, HLB-control
in the “good” farm becomes much more difficult because the highly infected psyllids from the “poor” farm
invade and contaminate the “good” farm. In this case, more aggressive psyllid control has to be applied
in the contaminated periphery of the good farm 4) HLB-control was found to be easier when applied to
large orchard surfaces (≥1000ha) rather than to smaller ones. 5) Young orchards which have multiple flushes
were more susceptible than mature ones with lesser flushes and required systemic insecticides to achieve
better control of the psyllid-vectors. In contrast to the five above factors which are characteristic of the
farm at onset of the management, the following factors are those that can be modified and through which
management can change the HLB incidence in the farm: 1) Number of inspections for early detection and
removal of symptomatic trees. The use of tractor-pulled platforms with two or four inspectors made surveys
more efficient and less strenuous. 2) Number of psyllid control operations, nature of insecticides, application
methods, prevention of insecticide resistance. 3) Acording to the HLB incidence, removed trees are replaced
or not replaced by reset trees. 4) Old, lesser productive citrus blocks are removed to prevent their role as
sources of inoculums (restructuring). 5) Last but not least, it was recommended that HLB-management be
XII INTERNATIONAL CITRUS CONGRESS 2012 - 7