Barry C. Kostyk

Insecticidal Suppression of Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae) Vector of Huanglongbing Pathogens

Diaphorina citri vectors pathogens that cause ‘huanglongbing’ or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005–2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24–68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76–100% nymphs or adults over 99–296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on individual or regional assessment of all factors.

Organic treatments for control of pepper weevil (Coleoptera: Curculionidae)

Abstract The pepper weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae) is a major pest of pepper (Capsicum spp.; Solanales: Solanaceae) in the southern United States, Mexico, Central America and the Caribbean. Feeding and oviposition cause flower and fruit abscission and internal fruit damage resulting in serious yield losses. Females lay eggs in flower buds and small fruits, shielding larvae from contact pesticides, leaving only the adult stage vulnerable. The purpose of this study was to investigate low-risk and organic products for use against the pepper weevil to provide both organic and conventional growers with more control options. A neem product (Ecozin® 1.2% ME), kaolin clay (Surround® WP), diatomaceous earth (Red Lake Earth®) and a product based on plant terpenes (Requiem®), were tested in lab and field trials for efficacy against pepper weevil. The neem product did not reduce feeding or oviposition in lab choice and no choice tests, so it was not tested in the field. Kaolin clay, diatomaceous earth and Requiem reduced feeding and oviposition in lab trials. Spring and fall field tests of these products were conducted in small plots along with a standard pesticide rotation of Actara and Vydate and an untreated control. The only treatment to increase marketable yield was the standard pesticide rotation. In the spring field trial, the standard treatment doubled yield per plant compared to the untreated controls but the yield was not different from those in the kaolin clay and surround plots. While the organic products did not increase marketable yield significantly, they did decrease overall damage, indicating possible usefulness in combination with conventional insecticides or in low population pressure by spraying early and following appropriate cultural practices such as adequate fallow periods and crop destruction. We recommend further testing of diatomaceous earth in particular in combination with conventional and organic insecticides as part of future IPM program research.

Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on Zucchini Squash, 2015

Sweetpotato whitefly, also known as silverleaf whitefly is a serious of pest of curcubit vegetables in southwest Florida. Feeding can result in loss of yield and fruit quality due to silverleaf disorder but watermelon growers can experience catastrophic losses from watermelon vine decline caused by squash vein yellowing virus transmitted by B. tabaci . We prepared three raised beds 32 inches wide on 6-ft centers and 430 ft long for this trial on 22 Jan at the Southwest Florida Research and Education Center in Immokalee FL. Two drip tapes with 8-inch emitter spacing and flow rate of 0.67 gpm/100 ft were laid on each bed which was then covered with whiteface polyethylene film and fumigated with 300 lbs/acre Pic-Clor 60 EC (chloropicrin 56.7% + 1-3 dichloropropene 37.1%) injected through …

Control of Asian Citrus Psyllid and Citrus Leafminer with Cyantraniliprole, Cyclaniliprole and Flonicamid: Summer, 2015

Asian citrus psyllid (ACP) is the key pest of citrus in Florida, responsible for the spread of huanglongbing or citrus greening disease. Feeding damage from CLM larvae facilitates the spread of citrus canker. Insecticides are critical for suppression of these two pests. The experimental block at the Southwest Florida Research and Education Center consisted of 5-yr-old sweet orange “Hamlin” trees bud grafted to “US-802” (Citrus grandis × Poncirus trifoliata) planted at a density of 308 trees/acre. Trees were irrigated with microsprinklers and subjected to conventional cultural practices. Eight treatments and an untreated check, seven trees per plot, were randomly distributed …

Foliar Sprays of Selective and Broad-Spectrum Insectcides to Control Asian Citrus Psyllid in Oranges: Summer, 2015

Asian citrus psyllid (ACP) is the key pest of citrus in Florida, responsible for the spread of huanglongbing or citrus greening disease. Effective insecticides with diverse modes of action are needed to control this pest and reduce selection for insecticide resistance. The experimental block at the Southwest Florida Research and Education Center consisted of 5-yr-old sweet orange “Hamlin” trees bud grafted to “US-802” ( Citrus grandis  ×  Poncirus trifoliata ) planted at a density of 308 trees/acre. Trees were irrigated with micro-sprinklers, subjected to conventional cultural practices and pruned to induce new …

Control of Sweetpotato Whitefly With Labeled, Experimental, and Biological Insecticides on Staked Tomatoes, Fall 2013, A

SWF is a destructive pest of tomato in Florida, primarily in its role as a vector of tomato yellow leaf curl virus, which causes catastrophic yield losses, especially when infection occurs early in the crop cycle. The whitefly is also a pest in its own right, causing plant debilitation and irregular ripening of the fruit. Two sets of three raised beds 420 ft in length were prepared and fumigated with MBC50/50 at 100 lbs/acre at the Southwest Florida Research and Education Center in Immokalee, FL, on 17 Aug, and 50% of the expected nutrient requirement was incorporated as 10-2-10 NPK dry fertilizer. Two drip tapes with 8-inch emitter spacing were laid on each bed, as it was covered with black polyethylene film mulch, and seedlings of ‘BHN 975’ obtained from a commercial greenhouse were transplanted on 4 …

Control of Sweetpotato Whitefly With Foliar Insecticides on Staked Tomatoes, Fall 2013

SWF biotype B continues to be a destructive tomato pest in Florida, mostly due to its role as a vector of tomato yellow leaf curl virus. Affected plants yield little or no fruit when infected young. For this trial, two sets of three beds 420 ft in length were prepared on 15 Aug at the Southwest Florida Research and Education Center in Immokalee, FL. Dry fertilizer (10-2-10 NPK) was incorporated at a rate of 1,000 lb/acre, beds were fumigated with PicClor 60 EC at 240 lbs/acre, and each bed received two drip tapes with 8-inch emitter spacing and was covered with black polyethylene film mulch. Seedlings of ‘Soraya’ obtained from a commercial greenhouse were transplanted 18 inches apart on 6 Sep. Fertilizer was injected during the course of the growing season as liquid 7-2-7 through the drip, and Actigard (0.33–0.50 oz/acre), …

Acaricidal Control of Citrus Rust Mites, 2014: Table 1

Russeting of fruit caused by feeding of the citrus rust mite (CRM) is of major concern to fresh fruit growers but, when severe, also reduces juice yield and quality. Given its potential for damage and short generation time, an adequate “tool box” of products is needed against this persistent pest. This trial was conducted at the Southwest Florida Research and Education Center on 18-yr-old “Valencia” orange trees planted at 15 by 22 ft spacing on double-row beds spacing running north–south. …

Control of Pickleworm and Melonworm on Cantaloupe With Foliar Applied Insecticides, 2014

Pickleworm is a destructive pest of squash, cucumber, and cantaloupe in south Florida, feeding first on flowers, then boring into fruit and reducing yield. Melonworm may defoliate plants, destroy flowers, and also damage fruit. For this trial, greenhouse-raised seedlings were transplanted on 6 Mar 2014 into raised beds covered with black polyethylene mulch at the Southwest Florida Research and Education Center in Immokalee, FL. Two beds on 12-ft centers and 430 ft long were used, each provided with two drip lines emitting at …

Tank Mixes and Premixes of Experimental and Labeled Insecticides for Control of Asian Citrus Psyllid and Citrus Leafminer on Oranges, Summer, 2014

ACP vectors the bacterium Candidatus Liberibacter asiaticus, causal organism of citrus greening disease or “Huanglongbing.” Feeding damage from CLM larvae facilitates the spread of citrus canker caused by Xanthomonas axonopodis pv. citri . Effective control measures are needed upon which to develop integrated management strategies against these pests and the associated diseases in Florida citrus. The experimental block in a commercial grove near LaBelle, Florida consisted of 7-yr-old sweet orange “Hamlin” trees planted at a density of 132 trees/acre. …