Annona Species Monograph.pdf - Crops for the Future

Chapter 10. Agronomy
solution of macerated leaves of the Neem (Azadirachta indica) tree. The
fruit-spotting bug (Amblyphelta nitida) is considered a serious annona pest in
Australia and its damage resembles the symptoms of black canker or diplodia
rot (Nakasone and Paull, 1998). Where possible, if damage is limited,
chemical use should be avoided.
10.3.7.2 Diseases
Major and minor diseases of annona trees have frequently been described
(Table 10-14) (George et al., 1987; Junqueira et al., 1996; Pinto and Silva,
1996; Kavati et al., 1997; Rebollar-Alviter et al., 1997; Nakasone and Paull,
1998; SPT-TCA, 1999; Nava and Díaz, 2000). The intensity of the damage
and the control methods differ in a number of ways, according to country and
region where the attack occurred.
The most important root diseases caused by fungi are damping-off
(Rhizoctonia solani and Fusarium spp.) and black root rot (Phytophthora
spp., Cylindrocladium clavatum and Sclerotium rolfsii), whose attacks occur
mainly on nursery seedlings, but also occasionally on adult plants (Melo et
al., 1983; Junqueira et al., 1996). Although these diseases are caused by
different species, heavy clay soils and high relative humidity (RH) are the
main contributing factors for attacks. In addition, the symptoms and damage
(wilting and death of seedlings and adult plants) are similar (Torres and
Sánchez, 1992; Agustín and Alviter, 1996; Junqueira et al., 1996). To control
these diseases, the soil can be treated with a solarization system (see topic
10-1.1 and Plate 2). The use of resistant rootstocks, such as custard apple,
appears to be an adequate form of management to avoid attack of these fungi
(Kavati et al., 1997), but is not yet widely used.
The base of seedlings or adult plants can be sprayed with a fungicide solution
of benomyl 0.1% (Junqueira et al., 1996) if necessary. Seedlings can also be
drenched with 0.1% Bavistin at 10-12 day intervals (Singh, 1992).
Table 10-14. Major and selected minor diseases of Annona species
Common Name Specific Name Affected Plant
Parts
Major Diseases
Damping-off, Rhizoctonia solani Root and base of
Black rot (Thanatephorus
trunk
cucumeris),
Phytophthora spp.,
Cylindrocladium
clavatum, Sclerotium
rolfsii (Athelia rolfsii)
Country/Region
Universal
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