Decreased Water Use in a Super-Intensive Olive Orchard Mediates Arthropod Populations and Pest Damage

In Spain, water use in agriculture is expected to become limited by resources in the future. It is pertinent to study the effect of decreased irrigation on the presence of pests, plant damage, and arthropod communities in a super-intensive olive orchard examined from 2017 to 2019. Arthropods were studied with visual and vacuum sampling methods in two irrigation treatments (T1—control and T2—Regulated Deficit Irrigation (RDI)). Univariate analyses showed that the total arthropod abundance was significantly greater in T1 than in T2 in 2018 and 2019, mostly due to Diptera Nematocera. Visual sampling revealed that the feeding damage produced by Eriophyidae (Trombidiformes) was significantly lower in T2 in 2018 and 2019: 10–40% of shoots were affected in the late season compared with 50–60% affected for T1. The feeding symptoms caused by Palpita unionalis Hübner (Lepidoptera: Crambidae) and Zelleria oleastrella (Milliere) (Lepidoptera: Yponomeutidae) were significantly less for T2 than for T1. Multivariate principal response curves showed significant differences between irrigation strategies in the 2018 and 2019 data for both sampling methods. In conclusion, irrigation schemes with restricted water use (T2—RDI) help to reduce the abundance of several types of pests in olive crops, especially of those that feed on the plants’ new sprouts.

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Deficit Water Irrigation in an Almond Orchard Can Reduce Pest Damage

Agronomy ◽

10.3390/agronomy11122486 ◽

2021 ◽

Vol 11 (12) ◽

pp. 2486

Author(s):

José Enrique González-Zamora ◽

Cristina Ruiz-Aranda ◽

María Rebollo-Valera ◽

Juan M. Rodríguez-Morales ◽

Salvador Gutiérrez-Jiménez

Keyword(s):

Deficit Irrigation ◽

Univariate Analysis ◽

Irrigation Treatment ◽

Response Curves ◽

Regulated Deficit Irrigation ◽

Pest Damage ◽

Visual Sampling ◽

Almond Orchards ◽

Tetranychus Urticae Koch ◽

Almond Orchard

Irrigated almond orchards in Spain are increasing in acreage, and it is pertinent to study the effect of deficit irrigation on the presence of pests, plant damage, and other arthropod communities. In an orchard examined from 2017 to 2020, arthropods and diseases were studied by visual sampling under two irrigation treatments (T1, control and T2, regulated deficit irrigation (RDI)). Univariate analysis showed no influence of irrigation on the aphid Hyalopterus amygdali (Blanchard) (Hemiptera: Aphididae) population and damage, but Tetranychus urticae Koch (Trombidiformes: Tetranychidae) damage on leaves was significantly less (50–60% reduction in damaged leaf area) in the T2 RDI treatment compared to the full irrigation T1 control in 2019 and 2020. Typhlocybinae (principal species Asymmetrasca decedens (Paoli) (Hemiptera: Cicadellidae)) population was also significantly lower under T2 RDI treatment. Chrysopidae and Phytoseiidae, important groups in the biological control of pests, were not affected by irrigation treatment. The most important diseases observed in the orchard were not, in general, affected by irrigation treatment. The multivariate principal response curves show significant differences between irrigation strategies in 2019 and 2020. In conclusion, irrigation schemes with restricted water use (such as T2 RDI) can help reduce the foliar damage of important pests and the abundance of other secondary pests in almond orchards.

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