Management alternatives for Carmenta theobromae (Busck, 1910) (Lepidoptera: Sesiidae) and Simplicivalva ampliophilobia (Lepidoptera: Cossidae), limiting pests of guava in Colombia.

The larval stages of Carmenta theobromae Busck (1910) and Simplicivalva ampliophilobia Davis, Gentili-Poole and Mitter (2008) attack the subcortical zone and pith in guava trees, respectively, in the first productive nucleus of fruit trees in Colombia: Hoya del Río Suárez (HRS). The presence of pest insects has been reported in 98% of the farms sampled in HRS (n = 124), with up to 96 and 11 simultaneous larvae per tree, respectively. Although the aspects of the basic biology and life cycle of both pests have been resolved, there are no strategies for managing populations in the field. Therefore, the aim of this study was to evaluate different management alternatives under laboratory and field conditions in HRS. In laboratory conditions, a completely randomized design was used in two separate experiments, each with six treatments: T1: Spinosad (a mixture of Spinosad A and D); T2: S-1,2-di(ethoxycarbonyl) ethyl 0,0-dimethylphosphorodithioate (chemical control); T3: Lecanicillium lecanii; T4: Beauveria bassiana; T5: Mix of B. bassiana and B. brongniartii, and T6: distilled water (control). The number of dead larvae per replicate per treatment was evaluated (DL), with experimental units of five and three larvae, respectively. In the field, to the two best alternatives found for each pest in the laboratory, pruning and keeping the area around the plants free of weeds were added as cultural management, in two separate additional experiments, each with three larvae as experimental unit per treatment. For C. theobromae, the best laboratory alternatives were chemical control (DL: 3.78) and L. lecanii (DL: 2.33), followed without statistical differences by B. bassiana (DL: 1.67). In the field, the virulence of B. bassiana improved (DL: 3), and together with pruning and keeping the area around the plants clear of weeds (DL: 3), they stood out as the best alternatives. For S. ampliophilobia under laboratory conditions, the best alternatives were Spinosad (2.74) and chemical control (DL: 2.66), without significant difference. In the field, there were no statistical differences between the alternatives, except for the control. This statistical parity of cultural practices, and biological and chemical management is an argument in favor of the use of the former to the detriment of the third, especially when the harmful effects of the molecule S-1,2 di (ethoxycarbonyl) ethyl 0, 0-dimethyl phosphorodithioate have been proven in air, water and agricultural soils, in addition to its association with thyroid cancer in humans. This is a strong argument to favor the use of synergies of cultural and biological management methods framed in IPM, as opposed to the use of chemical agents whose harmful effects are strongly documented, and whose use is becoming increasingly prohibited.

Carmenta theobromae (), pest of guava in Colombia: biology, life cycle and natural enemies.

In 2006, the presence of a pest in guava was detected for the first time in the Province of Vélez, Santander, Colombia, known as the bander worm. Research on the biology of this pest is scarce and no natural enemies have been registered. The aim of the study was to establish the taxonomy, life cycle, damage (distribution, incidence, and severity) and natural enemies of this pest to be used in future integrated management programs. This study was carried out between May 2013 and December 2014. The taxonomy and morphological descriptions of the life stages of the bander worm correspond to Carmenta theobromae ( Busck, 1910). The life cycle in the field was 120-150 days, with 2-3 generations per year: egg, 15-30 days; larva, 60 days; pupa, 25 days; adult, 10-30 days. In the laboratory, the life cycle was 90-110 days: egg, 10-20 days; larval stages 6-7, 50-60 days; pupa, 20-22 days; adult, 5-7 days. The incidence was 98% in 124 farms with 9.87 ± 1.94 infested trees in relation to 40.74 ± 5.52 observed trees (n = 4,970). Severity was moderate (n = 48). The damage involves the removal of the bark to reach the vascular cambium. Biological control associated with the parasitoids Brachymeria pedalis and Telenomus sp., the entomopathogens Lecanicillium lecanii, Beauveria bassiana and B. brongniartii, and the practices like weeding and pruning represent a potential control strategy.

Guava borer worm (Lepidoptera: Cossidae), a limiting pest in guava: biology, lifecycle and management alternatives.

In 2006, a new limiting pest in guava was reported in the provincia de Vélez, Santander, Colombia, known as the borer worm. There is no knowledge of the biology of this pest so far. The aim of this study, conducted between May 2013 and December 2014, was to establish the taxonomy, lifecycle, damage (distribution, incidence, and severity), and control alternatives of this new limiting pest in guava, as input for an integrated management program. Results showed that this pest corresponds to Simplicivalva ampliophilobia (Davis et al., 2008). The life cycle in the field lasts 330-360 days, with one generation per year (univoltine): egg, 15-30 days; larva, 270 days; prepupa, 15 days; pupa, 30 days; adult, 15-30 days. Under laboratory conditions the lifecycle lasts 259-266 days, unknown egg state duration; larva, 7-8 instars, 210 days; pupa, 42 days; imago, 7-14 days (n = 60, α = 5%, 25.4 °C ± 4.93 °C, 55.6% ± 11.58% RH, photoperiod 0: 24). The incidence was 94% in 124 silvopastoral system farms with 7.51 ± 1.69 infested trees compared to 40.74 ± 5.52 observed trees (n = 4,970). The technified system showed a reduction in the average incidence of 50.83% compared to the silvopastoral guava cropping system. Severity was moderate (n = 48) in both systems. Morphometric descriptions of eggs, larvae, pupae, and imagos were performed. Damage and associated symptoms occur when larvae remove the conducting tissues of the plant adjacent to the medulla. Crop technification combined with the use of the parasitoid Apanteles sp., and the fungi Metarhizium anisopliae and Lecanicillium lecanii represent an alternative control for this pest.