Sugarcane yield loss in the ratoon crop carried over from the plant crop damaged by plant-parasitic nematode in a heavy clay field in Okinawa, Japan

Abstract

loss observed around the globe, including reductions of -% in Australia, -% in Brazil, and more than % in South Africa in plant and ratoon crops. As indicated by Blair and Stirling ( ), many of previous nematode studies in sugarcane fields were in sandy soil, in which Meloidogyne may be the most important plant-parasitic nematode species (PPN). Bull ( and ) reported a yield decline of % in plant crop and -% or more in the ratoon crop in a sandy sugarcane field infested with Pratylenchus. Bond et al. ( ) reported that in sandy soil sugarcane fields w it h Tyle nchorhynchu s, Me socr icone ma a n d Pratylenchus, in Louisiana, USA, -% of yield decline was observed in both plant and ratoon crops. Furthermore, Cadet and Spaull ( ) showed a % yield increase by a nematicide application against Meloidogyne and Pratylenchus, and yields in the ratoon crop were correlated with those in the plant crop in sandy soil in South Africa.Yet, studies for nematode and sugarcane in clay soil have been limited. Dropkin ( ) reported that the Many field experiments have revealed sugarcane yield loss due to plant-parasitic nematodes, especially in sandy soil, but limited in clay soil. We previously reported a % sugarcane yield reduction in the plant crop in a heavy clay soil due to lesion nematodes suppressing the number of sugarcane tillers in the early growth stage (Kawanobe et al., ). Yet, it is unknown whether such early growth inhibition in plant canes will affect the ratoon crop yield in clay soil. The objective of this study was to examine the carry-over effect of yield decline from the plant crop to the ratoon crop in a field with high clay content (> %), in which early growth inhibition, possibly due to lesion nematodes, was observed in a plant crop of sugarcane. Though the Pratylenchus population density remained unchanged among treatments (fosthiazate-treated, kg and . kg/ ha at spring planting, and non-treated control), after months (July) from the spring planting until the harvest of the ratoon crop, our study showed a -% higher yield of the ratoon crop in the fosthiazate-treated crop than in the non-treated control. The result in the plant crop carried over to the ratoon crop, and implied that the healthier root growth of the plant canes achieved by a one-time nematicide application would carry-over to the ratoon crop. The result also suggested that the number of tillers and cane length observed at months (July) in the ratoon crop might adequately reflect nematode damage and offer a good explanation for the level of the ratoon crop yield. Nematol. Res. ( ), -. ( )

Nematicidal activity of fipronil against Pratylenchus zeae in sugarcane

“…This suggests that P. zeae population densities in roots at the early growth period of sugarcane can affect yield. The nematicide fosthiazate showed much greater reduction in the number of the root-lesion nematodes in sugarcane field soils (Kawanobe et al, 2014(Kawanobe et al, , 2016 and in sugarcane roots (Kawanobe et al, 2019) in the early growth period than later in the season. These studies (Kawanobe et al, 2016(Kawanobe et al, , 2019 showed 20% more sugarcane yield in the spring-planted crop and the ratoon crop by applying fosthiazate.…”

“…The nematicide fosthiazate showed much greater reduction in the number of the root-lesion nematodes in sugarcane field soils (Kawanobe et al, 2014(Kawanobe et al, , 2016 and in sugarcane roots (Kawanobe et al, 2019) in the early growth period than later in the season. These studies (Kawanobe et al, 2016(Kawanobe et al, , 2019 showed 20% more sugarcane yield in the spring-planted crop and the ratoon crop by applying fosthiazate. Fipronil may not be as effective as fosthiazate at the dose applied in this study, yet it still suppressed P. zeae in sugarcane roots and resulted in greater sugarcane yields than the non-treated control.…”

“…The roots were cut into 1-2 cm pieces and homogenized in water with a blender (BL143GJP, T-fal, Tokyo, Japan) for 15 sec. From 1 g fresh root subsample, nematodes were extracted using the Baermann funnel method (Kawanobe et al, 2019), at room temperature and collected after 48 h. The soil in each pot was collected and passed through a 5 mm aperture sieve to remove rocks and debris, mixed well and kept at room temperature for no more than a day before nematodes were extracted. Nematodes were extracted from 20 g subsamples of soils using the Baermann funnel method (Ingham, 1994) at room temperature and collected after 72 h. Nematodes were counted and identified based on their morphological characters under a stereo-microscope (SZX10, Olympus, Tokyo, Japan).…”

“…Plant-parasitic nematodes are one of the major yield limiting factors of sugarcane production (Cadet and Spaull, 2005). Previous studies revealed that 20 to 30% sugarcane yield losses were observed for both plant and ratoon crops due to the root-lesion nematode, Pratylenchus zeae (Kawanobe et al, 2014(Kawanobe et al, , 2016(Kawanobe et al, , 2019. Despite the very significant yield losses caused by the nematode, no nematicide has been registered for the control of plant-parasitic nematodes on sugarcane in Japan.…”

Đánh giá bước đầu mật số tuyến trùng ký sinh cây mía canh tác chuyên canh và luân canh tại huyện Phụng Hiệp, tỉnh Hậu Giang

“…Các nghiên cứu ở Úc, Brazil và Nam Phi cho biết năng suất mía giảm từ 10% đến 30% do tuyến trùng ký sinh thực vật gây ra và đôi khi giảm hơn 40% do tuyến trùng ký sinh thực vật ở châu Phi (Cadet & Spaull, 2005). Các nghiên cứu trước đây (Kawanobe et al, 2016(Kawanobe et al, , 2019 chỉ ra khoảng 20% thiệt hại về năng suất khi trồng vụ xuân và các vụ mùa liên tiếp do tuyến trùng ký sinh thực vật gây ra (chủ yếu là Pratylenchus) ở Okinawa, Nhật Bản. Như vậy, sự tích lũy mật số của dịch hại qua nhiều vụ trồng liên tiếp, nhất là các vùng chuyên canh có thể liên quan đến sự suy giảm năng suất mía.…”