Cotton Pest Management: Part 4. A Brazilian Perspective

Braz. arch. biol. technol.

Silva

Zanúncio

et al. 2007

Section: B V U Lg a Riscontrasting

confidence: 64%

Competition between Catolaccus grandis (Hymenoptera: Pteromalidae) and Bracon vulgaris (Hymenoptera: Braconidae), parasitoids of the Boll Weevil

Braz. arch. biol. technol.

Silva

Zanúncio

et al. 2007

“…Integrated Pest Management in cotton is based mainly on the action of predators (Whitcomb & Bell, 1962;Ramalho, 1994), and parasitoids (Ruberson et al, 1994;Ramalho et al, 2000) to suppress pest populations. Insecticides are used only when pest populations threaten to exceed the economic threshold.…”

Section: Introductionmentioning

confidence: 99%

Susceptibility of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidea) to gamma-cyhalothrin under laboratory conditions

Pereira

Sci. agric. (Piracicaba, Braz.)

Zanúncio³

2005

Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is an important biological control agent of the cotton leafworm [Alabama argillacea (Hübner)] in the cotton crops in Brazil. The use of selective products such as pyrethroids has been emphasized in this agroecosystem. Then, the susceptibility of the predatory stinkbug P. nigrispinus to the pyrethroid insecticide gamma-cyhalothrin was studied in the laboratory. Nymphs and adults of the predator were exposed to seven concentrations of the gamma-cyhalothrin via topical contact and ingestion through treated water. The concentrations studied of this insecticide via topical application were relatively harmless for adults of P. nigrispinus (females: LC 50 = 143.5 ppm a.i., and males: LC 50 = 145.1 ppm a.i.) and 5th-instar nymphs (LC 50 = 103.9 ppm) as compared to via ingestion (females: LC 50 = 1.98 ppm a.i., males: LC 50 = 1.91 ppm a.i., and 5th-instar nymphs: LC 50 = 2.05 ppm a.i.). The use of pyrethroids and beneficial insects in IPM programs should be better evaluated. Key words: cotton, biological control, pyrethroid, selectivity, natural enemies SUSCETIBILIDADE DE Podisus nigrispinus (DALLAS) (HETEROPTERA: PENTATOMIDAE) A GAMMA-CYHALOTHRIN SOB CONDIÇÕES DE LABORATÓRIORESUMO: Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) é um importante agente de controle biológico do curuquerê [Alabama argillacea (Hübner)] na cultura do algodão no Brasil. O uso de produtos seletivos tais como piretróides tem sido enfatizado no agroecosistema do algodoeiro. Portanto, estudou-se em laboratório a suscetibilidade do percevejo predador Podisus nigrispinus (Dallas) ao inseticida piretróide gamma-cyhalothrin. As exposições via ingestão e aplicação tópica de ninfas de 5 o ínstar, fêmeas e machos de P. nigrispinus a gamma-cyhalothrin foram feitas, usando-se sete concentrações do inseticida. Gammacyhalothrin via aplicação tópica foi relativamente menos tóxico às formas adultas de P. nigrispinus (fêmeas: CL 50 = 143,5 ppm i.a. e machos: CL 50 = 145,1 ppm i.a.) e às ninfas de 5 o ínstar (CL 50 = 103,9 ppm) desse predador, quando comparado a sua utilização por ingestão (fêmeas: LC 50 = 1,98 ppm i.a., machos: LC 50 = 1,91 ppm i.a. e ninfas de para ninfas de 5 o instar: LC 50 = 2,05 ppm i.a.). Os resultados dessa pesquisa sugerem que o uso de piretróides em programas de MIP deve ser avaliado com bastante cautela. Palavras-chave: algodão, controle biológico, piretróide, seletividade, inimigo natural

“…The cotton, aphid Aphis gossypii Glover (Hemiptera: Aphididae) is a phytophagous, cosmopolitan (Celini and Vaillant 2004) and polyphagous (Oliveira et al 2008) species that is found during the development phase of cotton plants. A. gossypii is the main cotton pest in Brazil (Ramalho 1994) and various other countries (Leclant andDeguine 1994, Wu andGuo 2003). High densities of this pest can have negative impacts on cotton production.…”

Section: Introductionmentioning

confidence: 99%

Within-plant distribution of cotton aphid (Hemiptera: Aphididae) in cotton cultivars with colored fibers

Fernandes

Malaquias

et al. 2012

An. Acad. Bras. Ciênc.

We describe the vertical and horizontal distribution of the cotton aphid Aphis gossypii Glover within a cotton plant in two cotton (Gossypium hirsutum Linnaeus) cultivars (BRS Safira and BRS Rubí) with colored fiber over the time. Measurements of aphid population dynamics and distribution in the cotton plants were recorded in intervals of seven days. The number of apterous or alate aphids and their specific locations were recorded, using as a reference point the location of nodes on the mainstem of the plant and also those on the leaves present on branches and fruit structures. The number of apterous aphids found on the cultivar BRS Safira (56,515 aphids) was greater than that found on BRS Rubí (50,537 aphids). There was no significant difference between the number of alate aphids found on the cultivars BRS Safira (365 aphids/plant) and BRS Rubí (477 aphids/ plant). There were interactions between cotton cultivar and plant age, between plant region and plant age, and between cultivar and plant region for apterous aphids. The results of this study are of great importance in improving control strategies for A. gossypii in the naturally-colored cotton cultivars BRS Safira and BRS Rubí.