Density and phenology of the invasive mealybug Delottococcus aberiae on citrus: implications for integrated pest management

Abstract

Martínez-Blay, V.; Pérez-Rodríguez, J.; Tena, A.; Soto Sánchez, AI. (2018). Density and phenology of the invasive mealybug Delottococcus aberiae on citrus: implications for integrated pest management. Journal of Pest Science. 91(2):625-637.Aknowledgements We would like to thank the owners of the orchards for allowing us to use their 19 plantations and P. Bru (IVIA) and J. Catalán (IVIA) for their help in sampling. This research was 20 supported by two predoctoral grants (FPU to V. Martínez-Blay and Val I+d to J. Pérez-Rodríguez from 21 the Spanish Ministry of Education, Culture and Sport and Generalitat Valenciana, respectively), the 22 European grants FP7-IAPP #324475 'Colbics' and FP7-IRSES #612566 'Biomodic', and a national 23 project provided by INIA (Project No. RTA2014-00067). The authors thank Debra Westall (UPV) for 24 revising the manuscript.25 26 27 2 Abstract 28 Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a new invasive citrus pest in Spain. It 29 causes severe fruit distortions and, as a new invasive mealybug, there is a lack of information about its 30 biology. This research aims to examine the seasonal trend of D. aberiae in citrus, using several sampling 31 methods, as a first step to develop an integrated pest management program. Ten citrus orchards from 32 Eastern Spain were periodically sampled during three years using absolute (plant material) and relative 33 (corrugated cardboard band traps and sticky traps) sampling methods. The three sampling methods 34 showed that D. aberiae completes multiple generations per year, two of them being clearly defined and 35 resulting in high populations. D. aberiae peaked between May and June, damaging the developing fruit.36 Corrugated cardboard band traps were able to detect prepupa and pupa male instars and gravid females, 37 providing a quantitative measurement of D. aberiae density at its first population peak. The use of 38 corrugated cardboard band traps is recommended to monitor population levels and sticky traps to 39 determine male flight periods, representing simple sampling techniques to monitor D. aberiae. These 40 results will improve the sampling protocols and allow for the development of an integrated pest 41 management program.42 Keywords: corrugated and sticky traps, life cycle, sampling protocols, D. aberiae, citrus 43 44 45 Key message 46  Delottococcus aberiae is a new invasive citrus pest in Europe and its biology is unknown. 47  This work aims to study the density of developmental stages of D. aberiae throughout the year.48  Different sampling methods showed that D. aberiae completes several generations. Two of them 49 are clearly defined and result in high population levels. 50  These results are the first seasonal population trend of D. aberiae in citrus and may serve as a 51 basis for an integrated pest management program. 52 53 54 55 56 57 58 59 60 61 62 63 64

Seasonal Distribution and Movement of the Invasive Pest Delottococcus aberiae (Hemiptera: Pseudococcidae) Within Citrus Tree: Implications for Its Integrated Management

“…Identification was confirmed by molecular and taxonomic techniques (Beltrà et al 2012, Beltrà et al 2015 and after an unsuccessful eradication program, based on the extensive application of chemical treatments, with insecticides authorized against mealybugs in Spain, in the initially affected areas, D. aberiae became established in the region (Beltrà et al 2013b). Since then, the mealybug has been spreading, slowly but constantly, towards adjoining areas, becoming a significant pest in eastern Spain (Pérez-Rodríguez et al 2017, Martínez-Blay et al 2018b).…”

“…aberiae completes several generations throughout the year (Franco et al 2000, Martínez-Ferrer et al 2003, García-Marí 2012, Pérez-Rodríguez et al 2017, Martínez-Blay et al 2018b. Two generations are very clearly defined and result in high population levels between May and July.…”

“…The rest of the year, apparently, three more overlapping generations may occur, depending on the climatic conditions: one between January and February, another one between August and October and one more between October and December (Martínez-Blay et al 2018b). From May to July, nymphs and adults settle and feed on fruitlets.…”

“…From May to July, nymphs and adults settle and feed on fruitlets. However, unlike other mealybug species present in citrus in Spain, this feeding behavior causes severe direct damage to citrus fruits, distorting its shape (mainly protuberances around fruit calyx) and/or causing size reduction, which depreciates its commercial value (Pérez-Rodríguez et al 2017, Martínez-Blay et al 2018a, Martínez-Blay et al 2018b) (Supp Fig. S1 [online only]).…”

“…For example, Maconellicoccus hirsutus (Green) causes severe distortions on hibiscus shoots, leaves and flowers, reducing its production and marketability (Meyerdirk et al 2001, Chong et al 2015. Direct damage caused by D. aberiae has been observed in all citrus cultivated in eastern Spain (sweet oranges, mandarins and hybrids) (Pérez-Rodríguez et al 2017, Martínez-Blay et al 2018b. Recently, the damaging period has been established, including the phenological stages between flowering (March-April in eastern Spain conditions) and fruits with a diameter of 25-30 mm (around July in eastern Spain conditions) (Pérez-Rodríguez et al 2017, Martínez-Blay et al 2018b.…”