Thrips incidence in green beans and the degree of damage caused

Green bean production accounts for 2.4% of the total value of Australian vegetable production and was Australia's tenth largest vegetable crop in 2008-2009 by value. Australian green bean production is concentrated in Queensland (51%) and Tasmania (34%) where lost productivity as a direct result of insect damage is recognised as a key threat to the industry (AUSVEG, 2011). Green beans attract a wide range of insect pests, with thrips causing the most damage to the harvestable product, the pod. Thrips populations were monitored in green bean crops in the Gatton Research Facility, Lockyer Valley, South-east Queensland, Australia from 2002-2011. Field trials were conducted to identify the thrips species present, to record fluctuation in abundance during the season and assess pod damage as a direct result of thrips. Thirteen species of thrips were recorded during this time on bean plantings, with six dominant species being collected during most of the growing season: Frankliniella occidentalis, F. schultzei, Megalurothrips usitatus, Pseudanaphothrips achaetus, Thrips imaginis and T. tabaci. Thrips numbers ranged from less than one thrips per flower to as high as 5.39 thrips per flower. The highest incidence of thrips presence found in October/November 2008, resulted in 10.74% unmarketable pods due to thrips damage, while the lowest number of thrips recorded in April 2008 caused a productivity loss of 36.65% of pods as a result of thrips damage.

The effect of 3-5-6 TPA on fruit drop and fruit size in the lychee (Litchi Chinensis) cultivars 'Fay Zee Siu' (feizixiao) , 'Kaimana', 'Kwai Mai Pink', 'Souey Tung' and 'Tai So' (Mauritus)

Fruit drop can cause major yield losses in Australian lychee orchards, the severity varying with cultivar and season. Research in China, South Africa and Israel has demonstrated the potential for synthetic auxins used as foliar sprays to reduce fruit drop in lychee. Trials tested the efficacy of the synthetic auxin 3-5-6 trichloro-2-phridyl-oxyacetic acid (TPA) applied as a foliar spray at 50 ppm on fruit drop and fruit size on the cultivars ‘Fay Zee Siu’, ‘Kaimana’, ‘Kwai Mai Pink’, ‘Souey Tung’ and ‘Tai So’. TPA reduced fruit drop when applied to fruit greater than 12 mm in length but increased fruit drop when fruit were smaller. Fruit size at the time of application had less effect on the response than the level of natural fruit drop. When natural fruit drop was high, TPA significantly reduced it; by up to 18.7 in ‘Fay Zee Siu’, 37.1 in ‘Kaimana’, 39.8 in ‘Kwai Mai Pink’, 15.1 in ‘Souey Tung’ and 7.7 in ‘Tai So’. TPA was less effective when natural fruit drop was low. TPA increased the number of large fruit and frequently increased the number of small fruit at harvest. The small fruit were associated with an increase in the retention of fruit with poorly developed (chicken tongue) seed. Average fruit size was generally larger (up to 12.7 in ‘Souey Tung’ and 22 in ‘Tai So’) with TPA applications.