Post-emergence seedling damage due to vertebrate pests and its impact on soybean establishment

The quality of field crop establishment is an indicator of the productivity and yield quality of a given crop. Several biotic and abiotic factors, as well as cropping practices, affect the quality of field crop establishment. More specifically to soybean, recent studies quantified pre-emergence seedling losses and identified the associated causes of non-emergence. However, little is known about post-emergence seedling damage, mainly due to vertebrate pests, which represent an important problem for growers. A 2-year field observation was conducted to quantify near- and post-emergence seedling damage due to vertebrate pests. The common wood pigeon (Columba palumbus) and the European hare (Lepus europaeus) were associated with this kind of damage. The characteristic damage due to the common wood pigeon consisted of either partially-damaged cotyledons during emergence or completely uprooted seedlings at emergence. In contrast, damage due to the European hare consisted of chewed seedling or seedling parts. There was significant effect of year (p < 0.001) on the final rates of post-emergence seedling damage due to the wood pigeon but not on those due to the European hare. The final rates of post-emergence damage due to the wood pigeon were higher (32% for 2018 and 22% for 2020) compared with those owing to the European hare (18% for 2018 and 17% for 2020). The severity of damage due to vertebrate pests was related to the type of seedling damage that, in turn, affected the capacity of soybean to compensate for post-emergence seedling damage.

Crop protection.

Crop protection procedures have existed since the first attempts at early agriculture. While cultivation of a vast range of crops is vital our existence, these same plants are highly attractive to a diverse range of invertebrate and vertebrate pests, and disease pathogens. Competition from weed species also occurs on a worldwide scale. Even with the many forms of crop protection practised today, losses due to pests and diseases range from 10 to 90%, with an average of 35-40% for all potential food and fibre crops (Peshin, 2002).

Vertebrate Pests

This chapter discusses vertebrate pests. Vertebrates become destructive to turfgrass in most cases simply because an attractive food supply exists in the turfgrass or soil below. Most often that food is insects or earthworms. Vertebrate pests are usually either birds or mammals. The chapter explains the biology and distribution of these pests. It also provides recommendations for the control of avian and mammalian pests. To control turf-damaging birds, eliminating the attractive food supply is necessary. The control of mammalian pests, apart from eliminating the attractive food supply of turfgrass insects, is explored briefly, since the various methods of control are longstanding and not subject to frequent changes.

DEVELOPMENT OF VERTEBRATE PEST MANAGEMENT MODELS FOR SUGARCANE CROP

Sugarcane crop is heavily damaged by a complex of rodent species and wild boar. The damaged sugarcane becomes infested with microorganisms and other physiological stresses, resulting in reduction of weight and sugar recovery. In this regard a study was carried out to know the damage caused by rodents to four varieties of sugar cane grown at Thatta. In these studies maximum damage by rodents was observed to BL-4 (10.29±0.44%) variety followed by BL-129 (10.23±0.35) and Thatta-10 (7.31±0.22%) in the month of November. To manage the vertebrate pests Integrated Pest Management approach was tested and the pest management model is designed for its adoption by the sugarcane growers after research and practical studies. In these studies egg mixed brodifacoum bait proved the most promising one in achieving (92.55±0.55%) rat reduction followed by bromdiolone (89.87±0.6%) and Zinc Phosphide bait (84.10±1.00%). Paraffinized Zinc Phosphide Capsular Technology used to kill wild boar population proved very successful by reducing the activity upto 98.11 Percent on the fifth day. The proposed model is a combination of mechanical, chemical and habitat manipulation approaches, which will help to enhance the crop yield through minimizing pest infestation.

Aerial baiting and wild dog mortality in south-eastern Australia

ContextWild dogs, including dingoes and dingo cross-breeds, are vertebrate pests when they cause financial losses and emotional costs by harming livestock or pets, threaten human safety or endanger native fauna. Tools for lethal management of these animals currently include aerial baiting with poisoned baits. In New South Wales (NSW), Australia, aerial baiting was previously permitted at a rate of 40 baits km−1 but a maximum rate of 10 baits km−1 was subsequently prescribed by the Australian Pesticides and Veterinary Medicines Authority. The efficacy of these baiting rates has not been quantified in eastern Australia, undermining the value of the policy and rendering adaptive management efforts difficult, at best. AimTo quantify the mortality rate of wild dogs exposed to aerial baiting at historic and currently approved rates, i.e. 40 baits per kilometre and 10 baits per kilometre, respectively. MethodsWild dog mortality rates were measured at sites in mesic north-eastern NSW, where aerial baiting was applied to control wild dogs and contrasted with sites and individuals where no baiting was undertaken. In total, 132 wild dogs were trapped and fitted with GPS-VHF telemetry collars before annual aerial baiting programs. Collars were used to locate animals after aerial baiting and to determine the fates of individuals. Key results90.6% of collared wild dogs exposed to aerial baiting at 40 baits km−1 died, whereas only 55.3% of those exposed to 10 baits km−1 died (Welsh’s t=4.478, P=0.004, v=6.95). All wild dogs that were not exposed to toxic baits survived during the same periods. ConclusionManagers using aerial baiting to maximise wild dog mortality in mesic south-eastern Australia should use 40 baits km−1 rather than 10 baits km−1. ImplicationsWild dog population reduction for mitigation of livestock and faunal predation requires the application of efficacious control. The currently prescribed maximum aerial baiting rate of 10 baits km−1 is inadequate for controlling wild dog populations in mesic forest environments in NSW.